Impact of oxygen incorporation on interface optimization and defect suppression for efficiency enhancement in Cu_(2)ZnSn(S,Se)_(4)solar cells

Kesterite Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)solar cells suffer from severe carrier recombination,limiting the photovoltaic performance.Unfavorable energy band alignment at the p-n junction and defective front interface are two main causes.Herein,oxygen incorporation in CZTSSe via absorber air-annealing was developed as a strategy to optimize its surface photoelectric property and reduce the defects.With optimized oxygen incorporation conditions,the carrier separation and collection behavior at the front interface of the device is improved.In particular,it is found that oxygen incorporated absorber exhibits increased band bending,larger depletion region width,and suppressed absorber defects.These indicate the dynamic factors for carrier separation become stronger.Meanwhile,the increased potential difference between grain boundaries and intra grains combined with the decreased concentration of interface deep level defect in the absorber provide a better path for carrier transport.As a consequence,the champion efficiency of CZTSSe solar cells has been improved from 9.74%to 12.04%with significantly improved open-circuit voltage after optimized air-annealing condition.This work provides a new insight for interface engineering to improve the photoelectric conversion efficiency of CZTSSe devices.

Interface optimization and defects suppression via Na F introduction enable efficient flexible Sb_(2)Se_(3) thin-film solar cells

Sb_(2)Se_(3) with unique one-dimensional(1D) crystal structure exhibits exceptional deformation tolerance,demonstrating great application potential in flexible devices.However,the power conversion efficiency(PCE) of flexible Sb_(2)Se_(3) photovoltaic devices is temporarily limited by the complicated intrinsic defects and the undesirable contact interfaces.Herein,a high-quality Sb_(2)Se_(3) absorber layer with large crystal grains and benign [hkl] growth orientation can be first prepared on a Mo foil substrate.Then NaF intermediate layer is introduced between Mo and Sb_(2)Se_(3),which can further optimize the growth of Sb_(2)Se_(3)thin film.Moreover,positive Na ion diffusion enables it to dramatically lower barrier height at the back contact interface and passivate harmful defects at both bulk and heterojunction.As a result,the champion substrate structured Mo-foil/Mo/NaF/Sb_(2)Se_(3)/CdS/ITO/Ag flexible thin-film solar cell delivers an obviously higher efficiency of 8.03% and a record open-circuit voltage(V_(OC)) of 0.492 V.This flexible Sb_(2)Se_(3) device also exhibits excellent stability and flexibility to stand large bending radius and multiple bending times,as well as superior weak light photo-response with derived efficiency of 12.60%.This work presents an effective strategy to enhance the flexible Sb_(2)Se_(3) device performance and expand its potential photovoltaic applications.

Development of nickel based cermet anode materials in solid oxide fuel cells–Now and future

High temperature solid oxide fuel cell(SOFC)is the most efficient and clean energy conversion technology to electrochemically convert the chemical energy of fuels such as hydrogen,natural gas and hydrocarbons to electricity,and also the most viable alternative to the traditional thermal power plants.However,the power output of a SOFC critically depends on the characteristics and performance of its key components:anode,electrolyte and cathode.Due to the highly reducing environment and strict requirements in electrical conductivity and catalytic activity,there are limited choices in the anode materials of SOFCs,particularly for operation in the intermediate temperature range of 500–800C.Among them,Ni-based cermets are the most common and popular anode materials of SOFCs.The objective of this paper is to review the development of Ni-based anode materials in SOFC from the viewpoints of materials microstructure,performance and industrial scalability associated with the fabrication and optimization processes.The latest advancement in nano-structure architecture,contaminant tolerance and interface optimization of Ni-based cermet anodes is presented.And at the end of this paper,we propose and appeal for the collaborative work of scientists from different disciplines that enable the inter-fusion research of fabrication,microanalysis and modelling,aiming at the challenges in the development of Ni-based cermet anodes for commercially viable intermediate temperature SOFC or IT-SOFC technologies.

水系锌离子电池隔膜设计

Aqueous zinc-ion batteries(AZIBs)are attracting worldwide attention due to their multiple merits such as extreme safety,low cost,feasible assembly,and environmentally friendly enabled by water-based electrolytes.At present,AZIBs have experienced systematic advances in battery components including cathode,anode,and electrolyte,whereas research involving separators is insufficient.The separator is the crucial component of AZIBs through providing ion transport,forming contact with electrodes,serving as a container for electrolyte,and ensuring the efficient battery operation.Considering this great yet ignored significance,it is timely to present the latest advances in design strategies,the systematic classification and summary of separators.We summarize the separator optimization strategies mainly along two approaches including the modification of the frequently used glass fiber and the exploitation of new separators.The advantages and disadvantages of the two strategies are analyzed from the material types and the characteristics of different strategies.The effects and mechanisms of various materials on regulating the uniform migration and deposition of Zn2+,balancing the excessively concentrated nucleation points,inhibiting the growth of dendrites,and the occurrence of side reactions were discussed using confinement,electric field regulation,ion interaction force,desolvation,etc.Finally,potential directions for further improvement and development of AZIBs separators are proposed,aiming at providing helpful guidance for this booming field.