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Defect passivation hi lead triiodide perovskite solar cells te hnathawh that nan hman a ni nasa hle a, mahse defect hrang hrangin α-phase stability a nghawng dan erawh hriat chian a la ni lo Hetah hian density functional theory hmangin a vawi khat nan formamidine lead triiodide perovskite α-phase atanga δ-phase thlenga degradation pathway kan hmuchhuak a, phase transition energy barrier-a defect hrang hrangte nghawng dan kan zirchiang a ni. Simulation results chuan iodine vacancy hian degradation a thlen tam ber tih a sawi a, a chhan chu α-δ phase transition atana energy barrier nasa taka tihhniam a nih avangin perovskite surface-ah formation energy hniam ber a nei a ni. Perovskite chunglama tuiah a inthiar theih loh lead oxalate layer dense tak dah luh hian α-phase decomposition nasa takin a titawp a, iodine migration leh volatilization a veng a ni. Tin, he strategy hian interfacial nonradiative recombination nasa takin a tihhniam bakah solar cell efficiency chu 25.39% (certified 24.92%) ah a tisang bawk. Unpackaged device hian simulated 1.5 G air mass irradiation hnuaia darkar 550 chhung maximum power-a a thawh hnuah pawh a original 92% efficiency chu a la vawng reng thei a ni.
Perovskite solar cells (PSC)-te power conversion efficiency (PCE) chu certified record high 26%1 a tling tawh a ni. Kum 2015 atang khan tunlai PSC te chuan formamidine triiodide perovskite (FAPbI3) hi light-absorbing layer atan an duh zawk a, hei hi a thermal stability tha tak leh Shockley-Keisser limit 2,3,4 hnaih ber bandgap duh zawk a nih vang a ni. Vanduaithlak takin FAPbI3 film-te hian thermodynamically-in room temperature-ah black α phase atanga yellow non-perovskite δ phase-ah phase transition an nei a5,6. Delta phase lo awm tur ven nan hian complex perovskite composition hrang hrang siam a ni. He harsatna hi sutkian dan tlangpui chu FAPbI3 chu methyl ammonium (MA+), cesium (Cs+) leh bromide (Br-) ion inzawmkhawm nen chawhpawlh hi a ni7,8,9. Mahse, hybrid perovskites te hian bandgap broadening leh photoinduced phase separation an tuar a, hei hian a chhuak PSCs te performance leh operational stability a tichhe a ni10,11,12.
Tun hnaia zirchianna hrang hrangah chuan doping tel lo pure single crystal FAPbI3 hian a crystallinity tha tak leh defects hniam tak a neih avangin stability tha tak a nei tih hmuhchhuah a ni13,14. Chuvangin, bulk FAPbI3 crystallinity tihpun hmanga chhiatna tihtlem hi PSCs tha leh nghet tak neih theihna tura strategy pawimawh tak a ni2,15. Mahse, FAPbI3 PSC hnathawh chhung hian duh loh zawng yellow hexagonal non-perovskite δ phase-ah degradation a la awm thei tho16. Hetiang hi a tlangpuiin hmun chhia tam tak awmna avanga tui, lumna leh êng laka invenna hmun leh buh chi ramri a\angin a intan \hin17. Chuvangin FAPbI318 black phase stabilize nan surface/grain passivation a ngai a ni. Defect passivation strategy tam tak, low-dimensional perovskites, acid-base Lewis molecule, leh ammonium halide salt te dah luh te hian formamidine PSCs19,20,21,22 ah hmasawnna nasa tak a nei a ni. Tun thleng hian zirchianna zawng zawng deuhthaw hian solar cell-a carrier recombination, diffusion length leh band structure te ang chi optoelectronic property tehna atana defect hrang hrangte chanvo an ngaihtuah vek tawh a ni22,23, Entirnan, density functional theory (DFT) hmangin defect hrang hrangte formation energies leh trapping energy level te chu theoretically predict nan hman a ni a, hei hi practical passivation design kaihhruaina atan hman a ni nasa hle Defect a tlem chuan device stability a tha zawk tlangpui. Mahse, formamidine PSC-ah chuan defect hrang hrangte hian phase stability leh photoelectric property a nghawng dan mechanism chu a danglam vek tur a ni. Kan hriat dan chuan, defect-in cubic to hexagonal (α-δ) phase transition a thlen dan leh α-FAPbI3 perovskite phase stability-a surface passivation-in a chanvo a neih dan hriatthiamna bulpui chu hriat chian a la ni lo.
Hetah hian FAPbI3 perovskite black α-phase atanga yellow δ-phase a degradation pathway leh DFT hmanga α-to-δ-phase transition energy barrier-a defect hrang hrangte nghawng dan kan hmuchhuak a ni. Film siam leh device hman laia awlsam taka siam theih I vacancy te hian α-δ phase transition a tichhuak tam ber tura ngaih a ni. Chuvangin, in situ reaction hmangin FAPbI3 chungah tuiah a inthiar theih loh leh chemically stable dense layer of lead oxalate (PbC2O4) kan dah lut a. Lead oxalate surface (LOS) hian I vacancy siam a titawp a, heat, light leh electric field-in a tihchak chuan I ions te migration a veng bawk. Chuta chhuak LOS chuan interfacial nonradiative recombination nasa takin a tihhniam a, FAPbI3 PSC efficiency chu 25.39% (certified to 24.92%) thlengin a tisang a ni. Unpackaged LOS device hian simulated air mass (AM) 1.5 G radiation-a darkar 550 chuang zet maximum power point (MPP)-a a thawh hnuah a original efficiency 92% a vawng reng a ni.
FAPbI3 perovskite α phase atanga δ phase a inthlakna tur decomposition path zawng turin ab initio calculation kan ti hmasa a. Phase transformation process kimchang tak hmangin FAPbI3 cubic α-phase-a three-dimensional corner-sharing [PbI6] octahedron atanga FAPbI3 hexagonal δ-phase-a one-dimensional edge-sharing [PbI6] octahedron-a inthlak danglamna chu a thleng thei tih hmuhchhuah a ni. breaking 9. Pb-I hian step hmasa berah (Int-1) bond a siam a, a energy barrier chu 0.62 eV/cell a thleng a, hei hi Figure 1a-a kan hmuh ang hian a ni. Octahedron chu [0\(\bar{1}\)1] lam hawia a inthlak chuan hexagonal short chain chu 1×1 atanga 1×3, 1×4 ah a zau a, a tawpah chuan δ phase ah a lut ta a ni. Path pumpui orientation ratio chu (011)α//(001)δ + [100]α//[100]δ a ni. Energy distribution diagram atang hian a hnuaia stage hrang hranga FAPbI3 δ phase nucleation a nih hnuah α phase transition aiin energy barrier a hniam zawk tih a hriat theih a, chu chu phase transition a chak zawk dawn tihna a ni. A chiang e, α-phase degradation tihtawp kan duh chuan phase transition control hmasak ber hi a pawimawh hle.
a Phase transformation process veilam atanga dinglam – black FAPbI3 phase (α-phase), Pb-I bond cleavage hmasa ber (Int-1) leh Pb-I bond cleavage dang (Int-2, Int -3 leh Int -4) leh yellow phase FAPbI3 (delta phase) te a ni. b Intrinsic point defect hrang hrang atanga FAPbI3 α to δ phase transition-a energy barrier te. Dotted line hian ideal crystal (0.62 eV) energy barrier a tarlang a. c Lead perovskite chunglama primary point defect siamna chakna. Abscissa axis hi α-δ phase transition-a energy barrier a ni a, ordinate axis hi defect siamna energy a ni. Grey, yellow leh green-a shaded part te chu type I (low EB-high FE), type II (high FE) leh type III (low EB-low FE) te an ni. d Control-a FAPbI3 defect VI leh LOS siamna chakna. e I FAPbI3 control leh LOS-a ion migration laka invenna. f – gf control-a I ions (orange spheres) leh gLOS FAPbI3 (gray, lead; violet (orange), iodine (mobile iodine)) te inthlak danglamna schematic representation (khawi lamah: chunglam atanga thlir; dinglam: cross section, brown) carbon hmanga siam; a sen hring – nitrogen; sen – oxygen; pink hring – hydrogen) a ni. Source data hi source data file angin pek a ni.
Chumi hnuah chuan intrinsic point defect hrang hrang (PbFA, IFA, PbI, leh IPb antisite occupancy; Pbi leh Ii interstitial atom; leh VI, VFA, leh VPb vacancies te pawh tel) te nghawng dan chu systematic takin kan zirchiang a, chungte chu key factor anga ngaih a ni. atomic leh energy level phase tihchhiatna thlentu chu Figure 1b leh Supplementary Table 1-ah te hian tarlan a ni a, ngaihnawm tak chu defect zawng zawng hian α-δ phase transition-a energy barrier hi a ti tlem vek lo (Figure 1b). Formation energies hniam leh α-δ phase transition energy barrier hniam zawk nei defect te hi phase stability tichhe thei anga ngaih a ni tih kan ring. Tun hmaa kan sawi tawh ang khan lead-rich surface hi formamidine PSC27 tan chuan a tangkai hle nia ngaih a ni tlangpui. Chuvangin, lead-rich condition hnuaia PbI2-terminated (100) surface kan ngaihtuah ber a ni. Surface intrinsic point defect-a defect formation energy chu Figure 1c leh Supplementary Table 1-ah hian tarlan a ni a, energy barrier (EB) leh phase transition formation energy (FE) atanga thlirin heng defect te hi chi thum-ah then a ni. Type I (low EB-high FE): IPb, VFA leh VPb te hian phase transition-a energy barrier chu nasa takin tihtlem mah se, formation energies sang tak an nei a ni. Chuvangin, heng defect chi hrang hrangte hian phase transition-ah nghawng a nei tlem hle niin kan ngai a, a chhan chu an lo piang tlem hle a ni. Type II (high EB): α-δ phase transition energy barrier tha zawk avang hian anti-site defect PbI, IFA leh PbFA te hian α-FAPbI3 perovskite phase stability a tichhe lo. Type III (low EB-low FE): VI, Ii leh Pbi defect, formation energies hniam tak nei chuan black phase degradation a thlen thei. A bik takin FE leh EB VI hniam berte ngaihtuah chuan strategy tangkai ber chu I hna ruak tihtlem hi a ni tih kan ring.
VI tihtlem nan FAPbI3 chunglam siam that nan PbC2O4 dense layer kan siam a. Organic halide salt passivator phenylethylammonium iodide (PEAI) leh n-octylammonium iodide (OAI) te nen khaikhin chuan mobile halogen ion nei lo PbC2O4 hi chemically stable a ni a, tuiah a insoluble lo a, stimulation a nih chuan awlsam takin a deactivate thei a ni. Perovskite chunglam tui leh electric field stabilization tha tak. Tuiah hian PbC2O4 hi 0.00065 g/L chauh a ni a, hei hi PbSO428 aiin a hniam zawk daih. Chu aia pawimawh zawk chu, in situ reaction hmangin perovskite film-ah LOS dense leh uniform layer te chu soft takin siam theih a ni (a hnuaia mi hi en la). Supplementary Figure 1-a kan hmuh angin FAPbI3 leh PbC2O4 inkara interfacial bonding DFT simulations kan ti a, Supplementary Table 2-ah hian LOS injection hnua defect formation energy tarlan a ni. LOS hian VI defects formation energy chu 0.69–1.53 eV a tipung mai bakah migration surface leh exit surface-a I activation energy a tipung tih kan hmuchhuak bawk (Figure 1e). Stage hmasa berah chuan I ions te chu perovskite surface-ah an migrate a, VI ion te chu lattice position-ah energy barrier 0.61 eV neiin an awm ta a ni. LOS hman a nih hnuah steric hindrance effect avang hian I ion te migration atana activation energy chu a pung a. 1.28 eV a ni. Perovskite leilung atanga I ion chhuakte an kal chhuah lai hian VOC-a energy barrier pawh control sample aiin a sang zawk bawk (Fig. 1e). Control leh LOS FAPbI3-a I ion migration pathways schematic diagram chu Figure 1 f leh g-ah hian tarlan a ni. Simulation result atanga a lan dan chuan LOS hian VI defects siam leh I volatilization a titawp thei a, chu chuan α to δ phase transition nucleation a titawp thei a ni.
Oxalic acid leh FAPbI3 perovskite inkara reaction chu an test a. Oxalic acid leh FAPbI3 solution te an pawlh hnuah white precipitate tam tak a lo awm a, hei hi Supplementary Figure 2-a kan hmuh ang hian a ni a, powder product chu X-ray diffraction (XRD) (Supplementary Figure 3) leh Fourier transform infrared spectroscopy (FTIR) (Supplementary Figure 4) hmangin PbC2O4 material thianghlim a nih thu an hmuchhuak a ni. Oxalic acid hi room temperature-ah isopropyl alcohol (IPA)-ah a inthiar nasa hle tih kan hmu a, a solubility chu 18 mg/mL vel a ni a, hei hi Supplementary Figure 5-a kan hmuh angin a hnu lama processing a awlsam phah a, IPA, common passivation solvent angin hun rei lote chhungin perovskite layer a tichhe lo Chuvangin, perovskite film chu oxalic acid solution-ah thun emaw, oxalic acid solution chu perovskite-ah spin-coating emaw hmangin, a hnuaia chemical equation ang hian perovskite film chung lamah PbC2O4 te tak te leh dense tak chu rang takin kan hmu thei a ni: H2C2O4 + FAPbI3 = PbC2O4 + FAI +HI. FAI hi IPA-ah a hmin thei a, chutiang chuan chaw siam laiin paih chhuah theih a ni. LOS thickness hi reaction time leh precursor concentration hmangin control theih a ni.
Scanning electron microscopy (SEM) hmanga control leh LOS perovskite film thlalak te chu Figure 2a,b-ah hian tarlan a ni. Results atanga a lan dan chuan perovskite surface morphology chu a vawng tha hle a, grain surface ah hian fine particle tam tak a awm a, hei hian in-situ reaction atanga siam PbC2O4 layer a entir tur a ni. LOS perovskite film hian control film (Supplementary Figure 7) nena khaikhin chuan a surface a hrual deuh (Supplementary Figure 6) a, water contact angle a lian zawk bawk (Supplementary Figure 7). High-resolution transverse transmission electron microscopy (HR-TEM) hmangin a chunglam layer chu a thliar hrang a ni. Control film (Fig. 2c) nen khaikhin chuan LOS perovskite chungah hian uniform leh dense thin layer 10 nm vel a thuk chu chiang takin a lang (Fig. 2d). High-angle annular dark-field scanning electron microscopy (HAADF-STEM) hmangin PbC2O4 leh FAPbI3 inkara inzawmna enfiah chuan FAPbI3 crystalline region leh PbC2O4 amorphous region awmna chu chiang takin kan hmu thei a ni (Supplementary Figure 8). Oxalic acid hmanga tihfai hnua perovskite chunglam awm dan chu X-ray photoelectron spectroscopy (XPS) hmanga teh a ni a, Figure 2e–g-ah hian kan hmu a ni. Figure 2e-ah hian C 1s peak 284.8 eV leh 288.5 eV vel chu CC leh FA signal bikte ta a ni. Control membrane nena khaikhin chuan LOS membrane hian 289.2 eV-ah peak dang a nei a, hei hi C2O42- vang a ni. LOS perovskite-a O 1s spectrum hian chemically distinct O 1s peak pathum 531.7 eV, 532.5 eV, leh 533.4 eV-ah a lantir a, hei hi deprotonated COO, intact oxalate group 30-a C=O leh OH component-a O atom-te nen a inmil a ni (Fig. 2e ). )). Control sample atan chuan O 1s peak tlemte chauh hmuh a ni a, hei hi a chunglama oxygen chemisorbed vang a ni thei. Pb 4f7/2 leh Pb 4f5/2 te control membrane characteristic hi 138.4 eV leh 143.3 eV ah a awm a ni. LOS perovskite hian Pb peak chu 0.15 eV velin binding energy sang zawk lam hawiin a inthlak tih kan hmu a, hei hian C2O42- leh Pb atom te inkara inzawmna chak zawk a lantir a ni (Fig. 2g).
a SEM images of control leh b LOS perovskite films, chunglam atanga thlir. c Control leh d LOS perovskite film-te chu high-resolution cross-sectional transmission electron microscopy (HR-TEM) hmanga enfiah a ni. E C 1s, f O 1s leh g Pb 4f perovskite film te chu resolution sang tak XPS a ni. Source data hi source data file angin pek a ni.
DFT result atanga a lan dan chuan theoretically chuan VI defect leh I migration hian awlsam takin α atanga δ ah phase transition a thlen thin niin an sawi. Tun hmaa report hrang hrangah chuan PC-based perovskite film atang hian I2 hi photoimmersion laiin rang takin a chhuak tih hmuhchhuah a ni a, chu chu film te chu light leh thermal stress-ah a dah a ni31,32,33. Lead oxalate-in perovskite α-phase a stabilizing effect a neihzia nemnghet turin control leh LOS perovskite film te chu transparent glass bottle-ah toluene awmnaah kan thun a, chutah chuan ni êng 1 hmangin 24 h chhung kan irradiate a. Ultraviolet leh visible light (UV-Vis) absorption kan teh a. ) toluene solution, Figure 3a-a kan hmuh ang hian. Control sample nena khaikhin chuan LOS-perovskite-ah hian I2 absorption intensity a hniam zawk hle tih hmuhchhuah a ni a, hei hian compact LOS hian light immersion laiin perovskite film atanga I2 chhuah chu a titawp thei tih a tilang a ni. Aged control leh LOS perovskite film thlalak te chu Figure 3b leh c inset-ah hian tarlan a ni. LOS perovskite hi a la dum a, control film tam zawk erawh chu yellow a lo ni tawh thung. Immersed film-a UV–visible absorption spectra chu Figs. 3b, c. Control film-a α nena inmil absorption chu chiang takin a tlahniam tih kan hmu a. X-ray measurement hmangin crystal structure evolution an document a ni. Darkar 24 chhung a eng hnuah control perovskite chuan yellow δ-phase signal chak tak (11.8°) a nei a, LOS perovskite erawh chuan black phase tha tak a la nei thung (Figure 3d).
Toluene solutions UV-visible absorption spectra a control film leh LOS film chu ni êng 1 hnuaiah darkar 24 chhung dah a ni. Inset-ah hian vial pakhat a lang a, chutah chuan film tin chu toluene volume inangah an thun a ni. b Control film leh c LOS film-a UV-Vis absorption spectra chu ni êng 1 hnuaia 24 h immersion hma leh immersion hnuah. Inset-ah hian test film thlalak a lang a. d Control leh LOS film-a X-ray diffraction pattern, 24 h exposure hma leh exposure hnua. Darkar 24 chhunga control film e leh film f LOS te SEM images. Source data hi source data file angin pek a ni.
Darkar 24 chhunga perovskite film-a microstructural changes awm dan enfiah turin scanning electron microscopy (SEM) measurement kan nei a, Figure 3e,f-a kan hmuh ang hian. Control film-ah chuan grain lian tak takte chu tihchhiat a ni a, needle te tak teah an chantir a, hei hi δ-phase product FAPbI3 morphology nen a inmil a ni (Fig. 3e). LOS film tan chuan perovskite grains te chu a dinhmun tha takah a awm reng a ni (Figure 3f). Results chuan I hloh hian black phase atanga yellow phase-a inthlakna chu nasa takin a tipung tih a nemnghet a, PbC2O4 erawh chuan black phase chu a stabilize thung a, I hloh a veng a ni.A chung lamah vacancy density chu grain bulk aiin a sang zawk hle a,34 he phase hi grain chung lamah a awm tam zawk a ni. a rualin iodine a chhuah a, VI a siam bawk. DFT-in a sawi lawk angin LOS hian VI defects siam a titawp thei a, I ion te perovskite surface-a migration a veng thei bawk.
Tin, boruak boruak (relative humidity 30-60%)-a perovskite film-te moisture resistance-a PbC2O4 layer-in nghawng a neih dan pawh zirchian a ni bawk. Supplementary Figure 9-a kan hmuh angin LOS perovskite chu ni 12 hnuah pawh a la dum a, control film chu a sen a ni thung. XRD tehnaah chuan control film hian FAPbI3 δ phase nena inmil 11.8°-ah peak chak tak a lantir a, LOS perovskite erawh chuan black α phase chu a vawng tha hle thung (Supplementary Figure 10).
Steady-state photoluminescence (PL) leh time-resolved photoluminescence (TRPL) hmangin lead oxalate-in perovskite chunglam a passivation effect a neih dan zirchian a ni. Fig. Figure 4a-ah hian LOS film hian PL intensity a tisang tih kan hmu a. PL mapping image-ah chuan 10 × 10 μm2 area pumpuiah LOS film intensity chu control film aiin a sang zawk a (Supplementary Figure 11), hei hian PbC2O4 hian perovskite film chu uniform takin a passivate tih a tilang a ni. Carrier dam chhung hi exponential function pakhat hmanga TRPL decay approximate hmanga teh a ni (Fig. 4b). LOS film carrier lifetime hi 5.2 μs a ni a, hei hi control film carrier lifetime 0.9 μs nei aiin a rei zawk hle a, hei hian surface nonradiative recombination tlahniam a tilang a ni.
Glass substrate-a perovskite film-te temporary PL-a steady-state PL leh b-spectra. c Device-a SP curve (FTO/TiO2/SnO2/perovskite/spiro-OMeTAD/Au) a ni. d EQE spectrum leh Jsc EQE spectrum te chu device tha ber atanga inzawmkhawm a ni. d Voc diagram-a perovskite device pakhat light intensity a innghahna. f ITO/PEDOT:PSS/perovskite/PCBM/Au clean hole device hmanga MKRC analysis tlangpui. VTFL hi trap filling voltage sang ber a ni. Heng data atang hian trap density (Nt) kan chhut a. Source data hi source data file angin pek a ni.
Lead oxalate layer-in device performance a nghawng dan zirchian nan hian traditional FTO/TiO2/SnO2/perovskite/spiro-OMeTAD/Au contact structure hman a ni. Device performance tha zawk neih theih nan methylamine hydrochloride (MACl) aiah perovskite precursor-a additive atan formamidine chloride (FACl) kan hmang a, FACl hian crystal quality tha zawk a pe thei a, FAPbI335 band gap a veng thei bawk (a chipchiar zawka tehkhin nan Supplementary Figure 1 leh 2 en rawh). ). 12-14-ah a awm). IPA hi antisolvent atan thlan a ni a, a chhan chu perovskite film-ah diethyl ether (DE) emaw chlorobenzene (CB)36 nena khaikhin chuan crystal quality tha zawk leh orientation duh zawk a pe a ni (Supplementary Figure 15 leh 16). PbC2O4 thickness chu uluk takin optimized a ni a, oxalic acid concentration siamrem hmangin defect passivation leh charge transport te chu a balance tha hle a ni (Supplementary Figure 17). Optimized control leh LOS device-te cross-sectional SEM images chu Supplementary Figure 18-ah tarlan a ni a, control leh LOS device-te tana current density (CD) curve pangngai chu Figure 4c-ah tarlan a ni a, extracted parameters chu Supplementary Table 3-ah tarlan a ni bawk a, Maximum power conversion efficiency (PCE) control cells 23.43% (22.94%), Jsc 25.75 mA cm-2 (25.74 mA cm-2), Voc 1.16 V (1.16 V) leh hnunglam (hma lam) scan a ni. Fill factor (FF) chu 78.40% (76.69%) a ni. PCE LOS PSC sang ber chu 25.39% (24.79%) a ni a, Jsc chu 25.77 mA cm-2 a ni a, Voc chu 1.18 V a ni a, FF chu reverse (forward Scan to) atanga 83.50% (81.52%) a ni. LOS device hian third-party photovoltaic laboratory rintlak takah certified photovoltaic performance 24.92% a nei a (Supplementary Figure 19). External quantum efficiency (EQE) hian integrated Jsc 24.90 mA cm-2 (control) leh 25.18 mA cm-2 (LOS PSC) a pe a, hei hi standard AM 1.5 G spectrum-a Jsc tehna nen a inmil hle a ni (Fig. .4d). ) . Control leh LOS PSCs atana PCE tehna statistical distribution chu Supplementary Figure 20-ah hian tarlan a ni.
Figure 4e-a kan hmuh angin Voc leh light intensity inzawmna chu PbC2O4-in trap-assisted surface recombination-a nghawng a neih dan zirchian nan an chhut a ni. LOS device tana fitted line slope chu 1.16 kBT/sq a ni a, hei hi control device tana fitted line slope (1.31 kBT/sq) aiin a hniam zawk a, hei hian LOS hi decoy hmanga surface recombination tihtawp nan a tangkai tih a nemnghet a ni. Figure-a kan hmuh angin hole device (ITO/PEDOT:PSS/perovskite/spiro-OMeTAD/Au)-a dark IV characteristic tehna hmangin perovskite film-a defect density quantitative-a tehna atan space charge current limiting (SCLC) technology kan hmang a ni. 4f Entir rawh. Trap density hi formula Nt = 2ε0εVTFL/eL2 hmanga chhut a ni a, ε chu perovskite film-a relative dielectric constant a ni a, ε0 chu vacuum-a dielectric constant a ni a, VTFL chu trap fill-na atana limiting voltage a ni a, e chu charge a ni a, L chu perovskite film thickness (650 nm) a ni. VOC device-a defect density chu 1.450 × 1015 cm–3 anga chhut a ni a, hei hi control device-a defect density aiin a hniam zawk a, chu chu 1.795 × 1015 cm–3 a ni.
Unpackaged device hi nitrogen hnuaia ni êng pumhlum hnuaiah maximum power point (MPP)-ah test a ni a, hun rei tak chhunga a performance stability enfiah a ni (Figure 5a). Darkar 550 hnuah pawh LOS device hian a efficiency sang ber 92% a la vawng reng a, control device performance erawh a performance hmasa 60%-ah a tlahniam thung. Device hlui chhunga element awmte insem darh dan chu time-of-flight secondary ion mass spectrometry (ToF-SIMS) hmangin an teh a (Fig. 5b, c). Upper gold control area-ah hian iodine tam tak a awm khawm tih hmuh tur a awm. Inert gas venhimna dinhmun hian boruak tichhe thei thil, moisture leh oxygen te chu a huam tel lo a, hei hian internal mechanism (ie, ion migration) te hi a mawhphurtu a ni tih a tilang a ni. ToF-SIMS result atanga a lan dan chuan Au electrode-ah I- leh AuI2- ion hmuhchhuah a ni a, hei hian perovskite atanga Au-a I a darh dan a tarlang a ni. Control device-a I- leh AuI2- ion-te signal intensity hi VOC sample aiin a let 10 velin a sang zawk a ni. Tun hmaa report hrang hrangah chuan ion permeation hian spiro-OMeTAD hole conductivity a tihhniam thuai thei a, top electrode layer-a chemical corrosion a thlen thei a, chu chuan device-a interfacial contact a tichhe thei a ni Au electrode chu lakchhuah a ni a, spiro-OMeTAD layer chu substrate atang chuan chlorobanzene solution hmangin a tifai a. Chumi hnuah chuan grazing incidence X-ray diffraction (GIXRD) hmangin film chu kan characterize a (Figure 5d). Results atanga a lan dan chuan control film hian 11.8° ah diffraction peak chiang tak a nei a, LOS sample ah erawh diffraction peak thar a lang lo thung. Results atanga a lan dan chuan control film-a I ion hloh nasa lutuk hian δ phase a siam a, LOS film-ah erawh chuan he process hi chiang takin a titawp thung.
Nitrogen boruakah unsealed device chu darkar 575 chhung MPP tracking chhunzawm zel a ni a, UV filter tel lovin ni êng 1 chhung a awm bawk. LOS MPP control device leh aging device-a b I- leh c AuI2- ion te ToF-SIMS hmanga sem darh. Yellow, green leh orange shade te hi Au, Spiro-OMeTAD leh perovskite te nen a inmil a ni. d MPP test hnua perovskite film GIXRD. Source data hi source data file angin pek a ni.
PbC2O4 hian ion migration a titawp thei tih finfiah nan temperature-dependent conductivity an teh a (Supplementary Figure 21). Ion migration activation energy (Ea) chu FAPbI3 film-a temperature hrang hrang (T)-a conductivity inthlak danglamna (σ) tehna hmanga teh a ni a, Nernst-Einstein relation hmangin: σT = σ0exp(−Ea/kBT), σ0 chu constant a ni a, kB chu Boltzmann constant a ni. Ea value chu ln(σT) versus 1/T slope atanga kan hmu a, chu chu control tan 0.283 eV leh LOS device tan 0.419 eV a ni.
A tawi zawngin, FAPbI3 perovskite degradation pathway leh α-δ phase transition-a energy barrier-a defect hrang hrangte nghawng dan hriat theihna tur theoretical framework kan pe a ni. Heng defect zingah hian VI defect te hian awlsam takin α atanga δ ah phase transition a thlen thei niin theoretically chuan an sawi a ni. FAPbI3 α-phase stabilize nan I vacancies siam leh I ions migration tihkhawtlai nan water-insoluble leh chemically stable dense layer of PbC2O4 dah a ni. He strategy hian interfacial non-radiative recombination nasa takin a tihhniam a, solar cell efficiency chu 25.39%-ah a tisang a, operating stability a ti sang bawk. Kan result hian defect-induced α to δ phase transition tihtawp a, formamidine PSCs tha leh nghet tak neih theihna tura kaihhruaina a pe a ni.
Titanium(IV) isopropoxide (TTIP, 99.999%) chu Sigma-Aldrich atangin lei a ni. Hydrochloric acid (HCl, 35.0–37.0%) leh ethanol (anhydrous) te chu Guangzhou Chemical Industry atangin an lei a ni. SnO2 (15 wt% tin(IV) oxide colloidal dispersion) chu Alfa Aesar atangin lei a ni. Lead(II) iodide (PbI2, 99.99%) chu TCI Shanghai (China) atangin lei a ni. A rilru a hah lutuk chuan a rilru a buai em em a, a rilru a hah lutuk chuan a rilru a buai em em bawk a. 2,2′,7,7′-tetrakis-(N , N-di-p) )-methoxyaniline)-9,9′-spirobifluorene (Spiro-OMETAD, ) ≥99.5%), lithium bis(trifluoromethane)sulfonylimide (Li-TFSI, 99.95%), 4-tert -butylpyridine (tBP, 96%) te chu Xi’an Polymer Light Technology Company (China) atangin lei a ni. N,N-dimethylformamide (DMF, 99.8%), dimethyl sulfoxide (DMSO, 99.9%), isopropyl alcohol (IPA, 99.8%), chlorobanzene (CB, 99.8%), acetonitrile (ACN) te a ni. Sigma-Aldrich atanga lei a ni. Oxalic acid (H2C2O4, 99.9%) chu Macklin hnen atangin lei a ni. Chemical zawng zawng hi siamthatna dang awm lovin an dawn angin an hmang vek a ni.
ITO emaw FTO substrate (1.5 × 1.5 cm2) te chu ultrasonically detergent, acetone, leh ethanol hmangin min 10 chhung an tifai a, nitrogen stream hnuaiah an vawt a ni. FTO substrate-ah TiO2 barrier layer dense tak chu ethanol (1/25, v/v)-a titanium diisopropoxybis(acetylacetonate) solution hmangin 500 °C-ah 60 min chhung dah a ni. SnO2 colloidal dispersion chu deionized water hmangin volume ratio 1:5-ah diluted a ni. Substrate thianghlim, UV ozone hmanga minute 20 chhunga tihfai tawhah chuan SnO2 nanoparticles film te tak te chu 4000 rpm-ah second 30 chhung dah a ni a, chutah chuan 150 °C-ah minute 30 chhung preheated a ni. Perovskite precursor solution atan chuan DMF/DMSO (15/1) mixed solvent-ah FAI 275.2 mg, PbI2 737.6 mg leh FACl (20 mol%) te chu a hmin a. Perovskite layer chu UV-ozone hmanga enkawl SnO2 layer chungah perovskite precursor solution 40 μL 5000 rpm-a ambient air-ah 25 s chhung centrifuging hmangin siam a ni. A vawi hnuhnung ber atanga second 5 hnuah MACl IPA solution 50 μL (4 mg/mL) chu antisolvent angin substrate-ah rang takin an paih a. Tichuan, film siam tharte chu 150°C-ah min 20 chhung annealed a, chutah chuan 100°C-ah min 10 chhung annealed leh a. Perovskite film chu room temperature-a tihlum hnuah H2C2O4 solution (1, 2, 4 mg dissolved in 1 mL IPA) chu 4000 rpm-ah 30 s chhung centrifuge-in perovskite chunglam chu passivate a ni. Spiro-OMeTAD solution siam chu 72.3 mg spiro-OMeTAD, 1 ml CB, 27 μl tBP leh 17.5 μl Li-TFSI (520 mg in 1 ml acetonitrile) te chu film-ah 4000 rpm-in 30 s chhungin spin-coated a ni. A tawpah chuan 100 nm thick Au layer chu vacuum-ah 0.05 nm/s (0~1 nm), 0.1 nm/s (2~15 nm) leh 0.5 nm/s (16~100 nm) rate-in an vawt chhuak a. ).
Perovskite solar cell-te SC performance chu Keithley 2400 meter hmangin solar simulator illumination (SS-X50) hmangin light intensity 100 mW/cm2-ah teh a ni a, calibrated standard silicon solar cells hmanga finfiah a ni. A danglamna a awm loh chuan SP curve chu nitrogen-a khat glove box-ah room temperature (~25°C)-ah forward leh reverse scan mode-ah (voltage step 20 mV, delay time 10 ms) teh a ni. PSC tehna atana effective area 0.067 cm2 hriat nan shadow mask hman a ni. EQE tehna hi ambient air-ah PVE300-IVT210 system (Industrial Vision Technology(s) Pte Ltd) hmangin an ti a, device-ah monochromatic light focus a ni. Device stability atan non-encapsulated solar cells testing chu nitrogen glovebox-ah UV filter tel lovin 100 mW/cm2 pressure-ah an nei a. ToF-SIMS hi PHI nanoTOFII time-of-flight SIMS hmanga teh a ni. Depth profiling hi 4 kV Ar ion gun hmanga siam niin, a area chu 400×400 μm a ni.
X-ray photoelectron spectroscopy (XPS) tehna chu Thermo-VG Scientific system (ESCALAB 250) hmangin monochromatized Al Kα (XPS mode atan) hmangin pressure 5.0 × 10–7 Pa hmangin an ti a, scanning electron microscopy (SEM) chu JEOL-JSM-6330F system hmangin an teh a ni. Perovskite film-te surface morphology leh roughness chu atomic force microscopy (AFM) (Bruker Dimension FastScan) hmangin an teh a ni. STEM leh HAADF-STEM hi FEI Titan Themis STEM-ah neih a ni. UV–Vis absorption spectra chu UV-3600Plus (Shimadzu Corporation) hmangin an teh a. Space charge limiting current (SCLC) chu Keithley 2400 meter-ah record a ni. Carrier dam chhung a chhiatna Steady-state photoluminescence (PL) leh time-resolved photoluminescence (TRPL) te chu FLS 1000 photoluminescence spectrometer hmangin an teh a ni. PL mapping images te hi Horiba LabRam Raman system HR Evolution hmangin an teh a ni. Fourier transform infrared spectroscopy (FTIR) chu Thermo-Fisher Nicolet NXR 9650 system hmangin an ti a.
He hnathawhnaah hian SSW path sampling method hmangin α-phase atanga δ-phase a phase transition path kan zirchiang a. SSW method-ah chuan potential energy surface kal dan chu random soft mode (second derivative) kalna lam atanga teh a ni a, hei hian potential energy surface chipchiar leh thil tum nei taka zir chian theihna a siam a ni. He hnathawhnaah hian path sampling hi atom 72 awmna supercell-ah tih a ni a, DFT level-ah initial/final state (IS/FS) pair 100 chuang lakkhawm a ni. IS/FS pairwise data set hmang hian initial structure leh final structure inzawmna kawng chu atom inkara inmilna nen a hriat theih a, chutah chuan variable unit surface-a two-way movement hmangin transition state method chu awlsam takin a hriat theih a ni. (VK-DESV) a ni. Transition state zawn hnuah chuan energy barrier te ranking hmangin barrier hniam berna kawng chu hriat theih a ni.
DFT chhut zawng zawng hi VASP (version 5.3.5) hmanga tih a ni a, hetah hian C, N, H, Pb, leh I atom te electron–ion inzawmna chu projected amplified wave (PAW) scheme hmanga entir a ni. Exchange correlation function hi Perdue-Burke-Ernzerhoff parametrization-a generalized gradient approximation hmanga sawifiah a ni. Plane wave-a energy limit chu 400 eV-ah dah a ni. Monkhorst–Pack k-point grid hi a lian zawng (2 × 2 × 1) a ni. Structure zawng zawng tan chuan lattice leh atomic position te chu maximum stress component 0.1 GPa hnuai lam leh maximum force component 0.02 eV/Å hnuai lam a nih thlengin fully optimized a ni. Surface model-ah chuan FAPbI3 chunglam chu layer 4 a awm a, a hnuai lam layer-ah chuan FAPbI3 taksa simulating atom fixed a awm a, a chung lam layer pathumte chu optimization process chhungin zalen takin an kal thei bawk. PbC2O4 layer hi 1 ML a thuk a ni a, FAPbI3 I-terminal surface-ah a awm a, chutah chuan Pb hi 1 I leh 4 O-ah a inzawm a ni.
Study design chungchang hriat belh duh chuan he thuziak nena inzawm Natural Portfolio Report Abstract hi en la.
He zirchianna chhunga data hmuh emaw, zirchian emaw zawng zawng chu thuziak chhuah tawhah te, chubakah a thlawptu information leh raw data file-ah te pawh a tel vek a ni. He zirchiannaa raw data tarlan te hi https://doi.org/10.6084/m9.figshare.2410016440 ah hian a awm a ni. He thuziak atan hian Source data pek a ni.
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