This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells(PSCs).Via A-site cation engineering,a weaker...This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells(PSCs).Via A-site cation engineering,a weaker electron-phonon coupling in perovskite has been achieved by introducing the structurally soft cyclohexane methylamine(CMA^(+))cation,which could serve as a damper to alleviate the mechanical stress caused by lattice oscillations,compared to the rigid phenethyl methylamine(PEA^(+))analog.It demonstrates a significantly lower non-radiative recombination rate,even though the two types of bulky cations have similar chemical passivation effects on perovskite,which might be explained by the suppressed carrier capture process and improved lattice geometry relaxation.The resulting PSCs achieve an exceptional power conversion efficiency(PCE)of 25.5%with a record-high opencircuit voltage(V_(OC))of 1.20 V for narrow bandgap perovskite(FAPbI_(3)).The established correlations between electron-phonon coupling and non-radiative decay provide design and screening criteria for more effective passivators for highly efficient PSCs approaching the Shockley-Queisser limit.展开更多
Nickel oxide(NiOx)has exhibited great potential as an inorganic hole transport layer(HTL)in perovskite solar cells(PSCs)due to its wide optical bandgap and superior stability.In this study,we have modulated the Ni26 v...Nickel oxide(NiOx)has exhibited great potential as an inorganic hole transport layer(HTL)in perovskite solar cells(PSCs)due to its wide optical bandgap and superior stability.In this study,we have modulated the Ni26 vacancies in NiOx film by controlling deposition temperature in a hot-casting process,resulting the change of coordination structure and charge state of NiOx.Moreover,the change of the HOMO level of NiOx makes it more compatible with perovskite to decrease energy losses and enhance hole carrier injection efficiency.Besides,the defect modulation in the electronic structure of NiOx is beneficial for increasing the electrical conductivity and mobility,which are considered to achieve the balance of charge carrier transport and avoid charge accumulation at the interface between perovskite and HTL effectively.Both experimental analyses and theoretical calculations reveal the increase of nickel vacancy defects change the electronic structure of NiOx by increasing the ratio of Ni3^+/Ni2^+-and improving the p-type characteristics.Accordingly,an optimal deposition temperature at 120℃enabled a 36.24%improvement in the power conversion efficiency compared to that deposited at room temperature(25℃).Therefore,this work provides a facile method to manipulate the electronic structure of NiOx to improve the charge carrier transport and photovoltaic performance of related PSCs.展开更多
Organic-inorganic metal halide perovskite solar cells(PSCs) have recently been considered as one of the most competitive contenders to commercial silicon solar cells in the photovoltaic field.The deposition process of...Organic-inorganic metal halide perovskite solar cells(PSCs) have recently been considered as one of the most competitive contenders to commercial silicon solar cells in the photovoltaic field.The deposition process of a perovskite film is one of the most critical factors affecting the quality of the film formation and the photovoltaic performance.A hot-casting technique has been widely implemented to deposit high-quality perovskite films with large grain size,uniform thickness,and preferred crystalline orientation.In this review,we first review the classical nucleation and crystal growth theory and discuss those factors affecting the hot-casted perovskite film formation.Meanwhile,the effects of the deposition parameters such as temperature,thermal annealing,precursor chemistry,and atmosphere on the preparation of high-quality perovskite films and high-efficiency PSC devices are comprehensively discussed.The excellent stability of hot-casted perovskite films and integration with scalable deposition technology are conducive to the commercialization of PSCs.Finally,some open questions and future perspectives on the maturity of this technology toward the upscaling deposition of perovskite film for related optoelectronic devices are presented.展开更多
Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a ...Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a template for perovskite growth,which is critical for enhancing the device performance.However,the current research on how the HTL promotes perovskite crystallization is insufficient.Here,4PADCB,a self-assembled monolayer(SAM)hole transport material,was optimized as a superior template for perovskite growth through comparative analysis;accordingly,compact perovskite film with vertical growth was prepared.The better matched energy level alignment between 4PADCB and perovskite suppressed nonradiative recombination at the interface and enabled rapid hole extraction.Moreover,high-quality perovskite film growth on 4PADCB exhibited lower Young's modulus and less residual stress.By integrating 4PADCB into p-i-n PSCs,the optimal device achieved a power conversion efficiency of 24.80%,with an open-circuit voltage of 1.156 V,thus achieving the best rank among devices without perovskite post-treatment,additives,dopants,or intermediate layers.Furthermore,the unencapsulated device demonstrated exceptional thermostability and photostability under maximum power point tracking.Thus,this work provides a new understanding for the development of novel SAMs and perovskite growth,and it is expected to further improve device performance.展开更多
Functional additives have recently been regarded as emerging candidates to improve the performance and stability of perovskite solar cells(PSCs).Herein,nicotinamide(N),2-chloronicotinamide(2Cl),and 6-chloronicotinamid...Functional additives have recently been regarded as emerging candidates to improve the performance and stability of perovskite solar cells(PSCs).Herein,nicotinamide(N),2-chloronicotinamide(2Cl),and 6-chloronicotinamide(6Cl)were employed as O-ligands to facilitate the deposition of MAPbI_(3)(MA=methylammonium)and MA-free FA_(0.88)Cs_(0.12)PbI_(2.64)Br_(0.36)(FA=formamidinium)perovskite films by multifunctional anchoring.By density functional theory(DFT)calculations and ultraviolet photoelectron spectroscopy(UPS)measurements,it is identified that the highest occupied molecular orbital(HOMO)level for additive modified MAPbI_(3)perovskite could reduce the voltage deficit for hole extraction.Moreover,due to the most favorable charge distribution and significant improvements in charge mobility and defect passivation,the power conversion efficiency(PCE)of 2Cl-MAPbI_(3)PSCs was significantly improved from 19.32%to 21.12%.More importantly,the two-dimensional grazing-incidence wide-angle X-ray scattering(GIWAXS)analysis showed that PbI_(2) defects were effectively suppressed and femtosecond transient absorption(TA)spectroscopy demonstrated that the trap-assisted recombination at grain boundaries was effectively inhibited in the 2Cl-MA-free film.As a result,the thermally stable 2Cl-MA-free PSCs achieved a remarkable PCE of 23.13%with an open-circuit voltage(V_(oc))of 1.164 V and an ultrahigh fill factor(FF)of 85.7%.Our work offers a practical strategy for further commercializing stable and efficient PSCs.展开更多
基金supported by the National Natural Science Foundation of China(U21A20331,81903743,22005322,22279151,and 22275004)National Science Fund for Distinguished Young Scholars(21925506).
文摘This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells(PSCs).Via A-site cation engineering,a weaker electron-phonon coupling in perovskite has been achieved by introducing the structurally soft cyclohexane methylamine(CMA^(+))cation,which could serve as a damper to alleviate the mechanical stress caused by lattice oscillations,compared to the rigid phenethyl methylamine(PEA^(+))analog.It demonstrates a significantly lower non-radiative recombination rate,even though the two types of bulky cations have similar chemical passivation effects on perovskite,which might be explained by the suppressed carrier capture process and improved lattice geometry relaxation.The resulting PSCs achieve an exceptional power conversion efficiency(PCE)of 25.5%with a record-high opencircuit voltage(V_(OC))of 1.20 V for narrow bandgap perovskite(FAPbI_(3)).The established correlations between electron-phonon coupling and non-radiative decay provide design and screening criteria for more effective passivators for highly efficient PSCs approaching the Shockley-Queisser limit.
基金financially supported by the National Natural Science Foundation of China NSFC(51702038)the Recruitment Program for Young Professionals+1 种基金the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial support。
文摘Nickel oxide(NiOx)has exhibited great potential as an inorganic hole transport layer(HTL)in perovskite solar cells(PSCs)due to its wide optical bandgap and superior stability.In this study,we have modulated the Ni26 vacancies in NiOx film by controlling deposition temperature in a hot-casting process,resulting the change of coordination structure and charge state of NiOx.Moreover,the change of the HOMO level of NiOx makes it more compatible with perovskite to decrease energy losses and enhance hole carrier injection efficiency.Besides,the defect modulation in the electronic structure of NiOx is beneficial for increasing the electrical conductivity and mobility,which are considered to achieve the balance of charge carrier transport and avoid charge accumulation at the interface between perovskite and HTL effectively.Both experimental analyses and theoretical calculations reveal the increase of nickel vacancy defects change the electronic structure of NiOx by increasing the ratio of Ni3^+/Ni2^+-and improving the p-type characteristics.Accordingly,an optimal deposition temperature at 120℃enabled a 36.24%improvement in the power conversion efficiency compared to that deposited at room temperature(25℃).Therefore,this work provides a facile method to manipulate the electronic structure of NiOx to improve the charge carrier transport and photovoltaic performance of related PSCs.
基金financially supported by the National Natural Science Foundation of China NSFC (51702038)the Sichuan Science and Technology Program (2020YFG0061)+1 种基金the Recruitment Program for Young Professionals. L. Ding thanks National Key Research and Development Program of China (2017YFA0206600)National Natural Science Foundation of China (51773045, 21772030, 51922032, 21961160720) for financial support。
文摘Organic-inorganic metal halide perovskite solar cells(PSCs) have recently been considered as one of the most competitive contenders to commercial silicon solar cells in the photovoltaic field.The deposition process of a perovskite film is one of the most critical factors affecting the quality of the film formation and the photovoltaic performance.A hot-casting technique has been widely implemented to deposit high-quality perovskite films with large grain size,uniform thickness,and preferred crystalline orientation.In this review,we first review the classical nucleation and crystal growth theory and discuss those factors affecting the hot-casted perovskite film formation.Meanwhile,the effects of the deposition parameters such as temperature,thermal annealing,precursor chemistry,and atmosphere on the preparation of high-quality perovskite films and high-efficiency PSC devices are comprehensively discussed.The excellent stability of hot-casted perovskite films and integration with scalable deposition technology are conducive to the commercialization of PSCs.Finally,some open questions and future perspectives on the maturity of this technology toward the upscaling deposition of perovskite film for related optoelectronic devices are presented.
基金supported by the National Science Fund for Distinguished Young Scholars(21925506)National Natural Science Foundation of China(U21A20331,81903743,22209192 and 62275251)+1 种基金Natural Science Foundation of Zhejiang Province(LY24F040002)China Postdoctoral Science Foundation(2022M713242).
文摘Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a template for perovskite growth,which is critical for enhancing the device performance.However,the current research on how the HTL promotes perovskite crystallization is insufficient.Here,4PADCB,a self-assembled monolayer(SAM)hole transport material,was optimized as a superior template for perovskite growth through comparative analysis;accordingly,compact perovskite film with vertical growth was prepared.The better matched energy level alignment between 4PADCB and perovskite suppressed nonradiative recombination at the interface and enabled rapid hole extraction.Moreover,high-quality perovskite film growth on 4PADCB exhibited lower Young's modulus and less residual stress.By integrating 4PADCB into p-i-n PSCs,the optimal device achieved a power conversion efficiency of 24.80%,with an open-circuit voltage of 1.156 V,thus achieving the best rank among devices without perovskite post-treatment,additives,dopants,or intermediate layers.Furthermore,the unencapsulated device demonstrated exceptional thermostability and photostability under maximum power point tracking.Thus,this work provides a new understanding for the development of novel SAMs and perovskite growth,and it is expected to further improve device performance.
基金This work was financially supported by the National Natural Science Foundation of China(51702038,U21A20331,51773212 and 81903743)the Sichuan Science&Technology Program(2020YFG0061)+1 种基金National Science Fund for Distinguished Young Scholars(21925506)Natural Science Foundation of Ningbo(2021J192).
文摘Functional additives have recently been regarded as emerging candidates to improve the performance and stability of perovskite solar cells(PSCs).Herein,nicotinamide(N),2-chloronicotinamide(2Cl),and 6-chloronicotinamide(6Cl)were employed as O-ligands to facilitate the deposition of MAPbI_(3)(MA=methylammonium)and MA-free FA_(0.88)Cs_(0.12)PbI_(2.64)Br_(0.36)(FA=formamidinium)perovskite films by multifunctional anchoring.By density functional theory(DFT)calculations and ultraviolet photoelectron spectroscopy(UPS)measurements,it is identified that the highest occupied molecular orbital(HOMO)level for additive modified MAPbI_(3)perovskite could reduce the voltage deficit for hole extraction.Moreover,due to the most favorable charge distribution and significant improvements in charge mobility and defect passivation,the power conversion efficiency(PCE)of 2Cl-MAPbI_(3)PSCs was significantly improved from 19.32%to 21.12%.More importantly,the two-dimensional grazing-incidence wide-angle X-ray scattering(GIWAXS)analysis showed that PbI_(2) defects were effectively suppressed and femtosecond transient absorption(TA)spectroscopy demonstrated that the trap-assisted recombination at grain boundaries was effectively inhibited in the 2Cl-MA-free film.As a result,the thermally stable 2Cl-MA-free PSCs achieved a remarkable PCE of 23.13%with an open-circuit voltage(V_(oc))of 1.164 V and an ultrahigh fill factor(FF)of 85.7%.Our work offers a practical strategy for further commercializing stable and efficient PSCs.
