Application of phenonaphthazine derivatives as hole-transporting materials for perovskite solar cells

Two electron-rich, solution-processable phenonaphthazine derivatives, 5,12-bis(N-[4,4'-bis-(phenyl) aminophen-4 ''-yl]}-phenonaphthazine (BPZTPA) and 5,12-bis{N-[4,4'-bis(methoxy-phenyl)aminophen-4'-phenonaphthazine (MeO-BPZTPA) have been designed and employed in the fabrication of perovskite solar cells. BPZTPA and MeO-BPZTPA exhibit excellent thermal stabilities, hole mobilities (similar to 10(-4) cm(2)/(V.s)) and suitable HOMO levels (-5.34 and-5.29 eV, respectively) relative to the valence band of the CH3NH3PbI3 and Au work function, showing their potential as alternative hole-transporting materials (HTMs). Meanwhile, the corresponding mesoporous TiO2/CH3NH3PbI3/HTM/Au devices are investigated, and the best power conversion efficiency of 10.36% has been achieved for MeO-BPZTPA without using p-type dopant. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Highly efficient solution-processed CZTSSe solar cells based on a convenient sodium-incorporated post-treatment method

In CZTSSe solar cells,a simple sodium-incorporation post-treatment method toward solution-processed Cu2Zn Sn S4precursor films is presented in this work.An ultrathin NaCl film is deposited on Cu2Zn Sn S4precursor films by spin-coating NaCl solution.In subsequent selenization process,the introduction of Na Cl is found to be benefacial for the formation of Cu2-xSe,which can further facilitate the element transportation,leading to dense and smooth CZTSSe films with large grains and less impurity Cu2Sn(S,Se)3phase.SIMS depth profiles confirm the gradient distribution of the sodium element in Na-doped absorbers.Photoluminescence spectra show that the introduction of appropriate sodium into the absorber can inhibit the band tail states.As high as 11.18% of power conversion efficiency(PCE)is achieved for the device treated with 5 mg mL^-1 NaCl solution,and an average efficiency of Na-doped devices is 10.71%,13%higher than that of the control groups(9.45%).Besides,the depletion width and the charge recombination lifetime can also have regular variation with sodium treatment.This work offers an easy modification method for high-quality Na-doped CZTSSe films and high-performance devices,in the meantime,it can also help to further understand the effects of sodium in CZTSSe solar cells.

Suppressing Charge Recombination in ZnO-Nanorod-Based Perovskite Solar Cells with Atomic-Layer-Deposition TiO2

ZnO nanorods are passivated with a TiO2 interracial layer and applied in the CH3NH3PbI3 perovskite solar cell, which prepared by the atomic layer deposition method show a positive effect on the tiff factor and power conversion efficiency. With TiO2 interracial passivation, the charge recombination in the ZnO/CH3NH3PbI3 interface is effectively suppressed and the maximum power conversion efficiency is enhanced from 11.9% to 13.4%.

Regulation of Zn/Sn ratio in kesterite absorbers to boost 10% efficiency of Cu_2ZnSn(S,Se)_4 solar cells

The Zn/Sn ratio in Cu2ZnSn（S, Se）4 （CZTSSe） films has been regulated to control the composition-related phase, defect, and photoelectric properties for high performance kesterite solar cells. It is found that the increase in the Zn/Sn ratio can slightly narrow the energy band gap to extend the light absorption range and improve the photocurrent. Optimal Zn/Sn ratio of 1.39 in CZTSSe film is obtained with the least secondary phase, the lowest defect density, and the longest charge recombination lifetime. Up to 10.1% photoelectric conversion efficiency has been achieved by this composition regulation.

Recent progress of colloidal quantum dot based solar cells

Colloidal quantum dot （CQD） solar cells have attracted great interest due to their low cost and superior photo-electric properties. Remarkable improvements in cell performances of both quantum dot sensitized solar cells （QDSCs） and FbX （X = S, Se） based CQD solar cells have been achieved in recent years, and the power conversion efficiencies （PCEs） ex- ceeding 12% were reported so far. In this review, we will focus on the recent progress in CQD solar cells. We firstly summarize the advance of CQD sensitizer materials and the strategies for enhancing carrier collection efficiency in QD- SCs, including developing multi-component alloyed CQDs and core-shell structured CQDs, as well as various methods to suppress interfacial carrier recombination. Then, we discuss the device architecture development of PbX CQD based solar cells and surface/interface passivation methods to increase light absorption and carrier extraction efficiencies. Finally, a short summary, challenge, and perspective are given.

原位制备MoO_3薄膜提高铜锌锡硫硒太阳能电池背界面接触性能（英文）

在空气中对钼基底进行退火处理,在钼表面形成MoO_3薄层.该MoO_3薄膜能有效抑制过厚Mo(S,Se)_2的形成.研究发现, MoO_3厚度随着温度的升高而增大,其中350°C形成的MoO_3厚度最为合适,既能够有效降低Mo(S,Se)_2的厚度,又不影响吸收层和钼电极接触,器件最高效率达到10.58%.这种方法不会引入其他杂质元素,操作简单方便.