Boosting MA-based two-dimensional Ruddlesden-Popper perovskite solar cells by incorporating a binary spacer

Two-dimensional Ruddlesden-Popper(2DRP)perovskite exhibits excellent stability in perovskite solar cells(PSCs)due to introducing hydrophobic long-chain organic spacers.However,the poor charge transporting property of bulky organic cation spacers limits the performance of 2DRP PSCs.Inspired by the Asite cation alloying strategy in 3D perovskites,2DRP perovskites with a binary spacer can promote charge transporting compared to the unary spacer counterparts.Herein,the superior MA-based 2DRP perovskite films with a binary spacer,including 3-guanidinopropanoic acid(GPA)and 4-fluorophenethylamine(FPEA)are realized.These films(GPA_(0.85)FPEA_(0.15))_(2)MA_(4)Pb_5I_(16)show good morphology,large grain size,decreased trap state density,and preferential orientation of the as-prepared film.Accordingly,the present 2DRP-based PSC with the binary spacer achieves a remarkable efficiency of 18.37%with a V_(OC)of1.15 V,a J_(SC)of 20.13 mA cm^(-2),and an FF of 79.23%.To our knowledge,the PCE value should be the highest for binary spacer MA-based 2DRP(n≤5)PSCs to date.Importantly,owing to the hydrophobic fluorine group of FPEA and the enhanced interlayer interaction by FPEA,the unencapsulated 2DRP PSCs based on binary spacers exhibit much excellent humidity stability and thermal stability than the unary spacer counterparts.

元认知深化研究生课程思政的多元化教学——以“太阳能电池性能提升技术”为例

本文以“太阳能电池性能提升技术”课程为案例,通过引入元认知理论,深化研究生专业课程的思政教育元素融入。详细探讨了元认知深化对专业课程思政教育的影响,包括专业深度与广度的统一、跨学科思维、自主学习与批判性思维、社会责任感、创新能力和个体终身学习态度。通过反思性学习活动,促进学生元认知能力提升,将专业知识学习与思政教育元素有机融合,培养全面发展的高层次专业人才。为培养全面素质研究生人才提供了有益思路,符合当前高等教育趋势,也契合中国特色社会主义培养目标。

钙钛矿太阳能电池的发展现状和未来趋势

1.Introduction Carbon neutrality is an important strategy to address the acute problems of resource and environmental constraints.Currently,afforestation,energy conservation,emissions reduction,and other measures have been adopted to offset the total amount of carbon dioxide and other greenhouse gas emissions generated by countries,businesses,products,activities,or individuals,with the aim of finally achieving zero net emissions(Fig.1(a)).

Stability of Sn-Pb mixed organic–inorganic halide perovskite solar cells:Progress,challenges,and perspectives

The exploration of low bandgap perovskite material to approach Shockley-Queisser limit of photovoltaic device is of great significance,but it is still challenging.During the past few years,tin–lead(Sn-Pb)mixed perovskites with low bandgaps have been rapidly developed,and their single junction solar cells have reached power conversion efficiency(PCE)over 21%,which also makes them ideal candidate as low bandgap sub-cell for tandem device.Nevertheless,due to the incorporation of unstable Sn^(2+),the stability issue becomes the vital problem for the further development of Sn-Pb mixed perovskite solar cells(PSCs).In this review,we are dedicated to give a full view in current understanding on the stability issue of SnPb mixed perovskites and their PSCs.We begin with the demonstration on the origin of instability of Sn-Pb mixed perovskites,including oxidation of Sn^(2+),defects,and interfacial layer induced instability.Sequentially,the up-to-date developments on the stability improvement of Sn-Pb mixed perovskites and their PSCs is systematically reviewed,including composition engineering,additive engineering,and interfacial engineering.At last,the current challenges and future perspectives on the stability study of Sn-Pb mixed PSCs are discussed,which we hope could promote the further application of Sn-Pb mixed perovskites towards commercialization.

Chiral cation promoted interfacial charge extraction for efficient tin-based perovskite solar cells

Pb-free Sn-based perovskite solar cells(PSCs) have recently made inspiring progress, and power conversion efficiency(PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial contact between commonly used hole transport layer(i.e., poly(3,4-ethylenedioxythio phene):poly(styrene sulfonate), PEDOT:PSS) and FASnI_(3) film, it is still challenging to effectively extract holes at the interface. Owing to the p-type nature of Sn-based perovskites, the efficient hole extraction is of particular significance to improve the PCE of their solar cells. In this work, for the first time, the role of chiral cations, a-methylbenzylamine(S-/R-/rac-MBA), in promoting hole transportation of FASnI_(3)-based PSCs is demonstrated. The introduction of MBAs is found to form 2D/3D film with lowdimensional structures locating at PEDOT:PSS/FASnI_(3) interface, which facilitates the energy level alignment and efficient charge transfer at the interface. Importantly, chiral-induced spin selectivity(CISS)effect of R-MBA_(2)SnI_(4)induced by chiral R-MBA cation is found to further assist the specific interfacial transport of accumulated holes. As a result, R-MBA-based PSCs achieve decent PCE of 10.73% with much suppressed hysteresis and enhanced device stability. This work opens up a new strategy to efficiently promote the interfacial extraction of accumulated charges in working PSCs.

Metal Halide Perovskite for next-generation optoelectronics:progresses and prospects

Metal halide perovskites(MHPs),emerging as innovative and promising semiconductor materials with prominent optoelectronic properties,has been pioneering a new era of light management(ranging from emission,absorption,modulation,to transmission)for next-generation optoelectronic technology.Notably,the exploration of fundamental characteristics of MHPs and their devices is the main research theme during the past decade,while in the next decade,it will be primarily critical to promote their implantation in the next-generation optoelectronics.In this review,we first retrospect the historical research milestones of MHPs and their optoelectronic devices.Thereafter,we introduce the origin of the unique optoelectronic features of MHPs,based on which we highlight the tunability of these features via regulating the phase,dimensionality,composition,and geometry of MHPs.Then,we show that owing to the convenient property control of MHPs,various optoelectronic devices with target performance can be designed.At last,we emphasize on the revolutionary applications of MHPs-based devices on the existing optoelectronic systems.This review demonstrates the key role of MHPs played in the development of modern optoelectronics,which is expected to inspire the novel research directions of MHPs and promote the widespread applications of MHPs in the next-generation optoelectronics.

Origin of High Efficiency and Long-Term Stability in Ionic Liquid Perovskite Photovoltaic

Environment-friendly protic amine carboxylic acid ionic liquids(ILs)as solvents is a significant breakthrough with respect to traditional highly coordinating and toxic solvents in achieving efficient and stable perovskite solar cells(PSCs)with a simple one-step air processing and without an antisolvent treatment approach.However,it remains mysterious for the improved efficiency and stability of PSCs without any passivation strategy.Here,we unambiguously demonstrate that the three functions of solvents,additive,and passivation are present for protic amine carboxylic acid ILs.We found that the ILs have the capability to dissolve a series of perovskite precursors,induce oriented crystallization,and chemically passivate the grain boundaries.This is attributed to the unique molecular structure of ILs with carbonyl and amine groups,allowing for strong interaction with perovskite precursors by forming C=O…Pb chelate bonds and N-H…I hydrogen bonds in both solution and film.This finding is generic in nature with extension to a wide range of IL-based perovskite optoelectronics.

Reductive ionic liquid-mediated crystallization for enhanced photovoltaic performance of Sn-based perovskite solar cells

Tin(Sn)-based perovskite solar cells(PSCs)have recently made inspiring progress,and certified power conversion efficiency(PCE)has reached impressive value of 14.8%.However,it is still challenging to realize efficient and stable 3D Sn-based PSCs due to the fast crystallization and easy Sn^(2+)oxidation of Sn-based perovskite.Herein,we reported the utilization of a reductive ionic liquid,methylamine formate(MAFa),to drive the controlled crystallization process and suppress Sn^(2+)oxidation of FASnI_(3)perovskite film.The coordination of C=O and Sn^(2+)and the hydrogen bonding of N-H···I between the MAFa and FASnI_(3)precursors are shown to be responsible for retarding the crystallization of FASnI_(3)during film-forming process,which promotes the oriented growth and reduced defect traps of the film.Moreover,the strong reducibility of–CHO groups in Fa−suppresses the oxidation of Sn^(2+)in the film.As a result,MAFa-modified 3D PSCs device could reach champion PCE of up to 8.50%,which is enhanced by 26.11%compared to the control device with PCE of 6.74%.Most importantly,the MAFa-modified device shows much improved stability compared to the control device under same conditions without encapsulation.This work adds key building blocks for further boosting the PCE and stability of Sn-based PSCs.