Improved Performance of Carbon Electrode Perovskite Solar Cells Using Urea Treatment in Two‐Step Processing. Issue 5 (6th February 2020)

• Record Type: Journal Article
• Authors: Xu, Tingting; Sun, Xuelin; Cao, Weiwei; Qin, Xiulan; Gurung, Ashim; Lv, Shaoshen; Chen, Yonghua; Chen, Lixin; Huang, Wei; Qiao, Qiquan
• Is Part Of: ChemNanoMat. Volume 6:Issue 5(2020)
• Page Start: 806
• Page End: 815
• Publication Date: 2020-02-06
• Subjects: carbon-based perovskite solar cell -- Lewis base additive -- urea -- grain size; Nanochemistry -- Periodicals; Nanostructured materials -- Periodicals; Nanochemistry; Nanostructured materials; Periodicals; 541.2
• DOI: 10.1002/cnma.201900681
• Languages: English
• ISSNs: 2199-692X

Abstract

Abstract: Perovskite solar cell has made a steady research progress with superior photovoltaic power conversion efficiency (PCE) over 25%. The quality of perovskite film is a key factor affecting device efficiency. Lewis bases such as urea, DMSO and thiourea etc. have been applied in perovskite precursor solutions for one step processing to effectively control the film morphology. Herein, we report urea treatment in a two‐step processing for obtaining high quality methylammonium lead triiodide perovskite (CH3 NH3 PbI3 ) film, which is accomplished by immersing the PbI2 film into the mixture solution of urea/methylammonium iodide (MAI). The optimized urea concentration in the MAI solution is 0.4 mg/mL, leading to larger‐sized and better crystalline perovskite grains than that without urea additive. The main function of the urea additive is the formation of the adduct MAI⋅PbI2 ⋅O=C(NH2 )2, retarding the crystallization process of the perovskite film. The steady‐state and time‐resolved photoluminescence measurements revealed that perovskite CH3 NH3 PbI3 grown using optimized concentration of urea has prolonged carrier lifetime and reduced carrier recombination. Finally, the carbon‐based perovskite solar cells fabricated from the optimal urea concentration of 0.4 mg/mL achieved the enhanced photovoltaic performance with the highest PCE of 13.10% and an average value of 11.34%, in comparison to devices without urea treatment exhibiting an average PCE of only 8.67%. Abstract : Quality of perovskite film has a great influence on the performance of perovskite solar cells. Herein, perovskite films with large‐sized grains were obtained by introducing Lewis base urea into the MAI solution for two‐step processing. Compared to the perovskite films without urea treatment, the perovskite films prepared with the optimal urea concentration of 0.4 mg/mL show fewer grain boundaries and defects, the carrier transport is also improved. The photovoltaic performance of the as‐fabricated carbon‐based perovskite solar cells achieves significant improvement up to 13%.