Unveiling the Effects of Hydrolysis-Derived DMAI/DMAPbI x Intermediate Compound on the Performance of CsPbI3 Solar Cells.

Youkui Xu,Hui Bian,Faguang Zhou,Shengzhong (Frank) Liu,Zhizai Li,Qian Wang,Hong Zhang,Zhiwen Jin,Liming Ding,Haoran Wang

doi:10.1002/advs.201902868

Abstract

Introducing hydroiodic acid (HI) as a hydrolysis‐derived precursor of the intermediate compounds has become an increasingly important issue for fabricating high quality and stable CsPbI3 perovskite solar cells (PSCs). However, the materials composition of the intermediate compounds and their effects on the device performance remain unclear. Here, a series of high‐quality intermediate compounds are prepared and it is shown that they consist of DMAI/DMAPbIx. Further characterization of the products show that the main component of this system is still CsPbI3. Most of the dimethylammonium (DMA+) organic component is lost during annealing. Only an ultrasmall amount of DMA+ is doped into the CsPbI3 and its structure is stabilized. Meanwhile, excessive DMA+ forms Lewis acid–base adducts and interactions with Pb2+ on the CsPbI3 surface. This process passivates the CsPbI3 film and decreases the recombination rate. Finally, CsPbI3 film is fabricated with high crystalline, uniform morphology, and excellent stability. Its corresponding PSC exhibits stable property and improved power conversion efficiency (PCE) up to 17.3%.

Highlights

Intermediate compounds has become an increasingly important issue for fab- Due to the intrinsic thermal and light ricating high quality and stable CsPbI3 perovskite solar cells (PSCs)
We proved the synPbI2 powder is DMAI/DMAPbIx powder
The composition for syn-CsPbI3 films and syn-PbI2 powders with different dimethyl formamide (DMF):hydroiodic acid (HI) ratios is basically similar, its show a noticeable effect on the phase transitions and optoelectronic because of soft mechanical nature of the hybrid perovskites.[50]

Summary

Introduction

Intermediate compounds has become an increasingly important issue for fab- Due to the intrinsic thermal and light ricating high quality and stable CsPbI3 perovskite solar cells (PSCs). In order to reduce the error, we performed a surface scan of unannealed and annealed syn-CsPbI3 film as shown in Figure S2 in the Supporting Information.

Results

Conclusion