Recently, inverted planar heterojunction (PHJ) perovskite solar cells have been developed rapidly by numerous preparations and relative optimizations. Sequential solution deposition is easy to manipulate but it is difficult to control the thickness and morphology of perovskite films. In this article, we report an improved sequential deposition, named twice dipping-vapor solution deposition (TD-VSD) technology, to accurately achieve superior perovskite films. It is demonstrated that the morphology of perovskite films depended on the substrate temperatures as well as the dipping times. The resulting solar cells showed the power conversion efficiency as high as 11.77% based on the ideal thickness and morphology. This work provides a simple but effective fabrication to well control the perovskite films and enhance the power conversion efficiency for inverted PHJ solar cells.

In the past two years, the power conversion efficiency (PCE) of organic-inorganic hybrid perovskite solar cells has significantly increased up to 20.1%. These state-of-the-art new devices surpass other third-generation solar cells to become the most promising rival to the silicon-based solar cells. Since the morphology of the perovskite film is one of the most crucial factors to affect the performance of the device, many approaches have been developed for its improvement. This review provides a systematical summary of the methods for morphology control. Introductions and discussions on the mechanisms and relevant hotspots are also given. Understanding the growth process of perovskite crystallites has great benefits for further efficiency improvement and enlightens us to exploit new technologies for large-scale, low-cost and high-performance perovskite solar cells.

A donor copolymer Poly\2,6-4,8-bis(2-ethylhexyl)benzo[1,2-b:3,4-b]dithiophene-5,8-2,3-b is(5-octylthiophen-2-yl)quinoxaline\ (PBDTThQx) with benzo[1,2-b:4,5-b]dithiophene and quinoxaline derivatives was synthesized and characterized with NMR, ultraviolet-visible spectroscopy, thermogravimetric analyses, and cyclic voltammetry. Photovoltaic devices with the configuration indium tin oxide-poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)-PBDTThQx-[6,6]-phenyl-C-61-butyric acid methyl ester (PC61BM)-LiF-Al were fabricated, in which PBDTThQx performed as the electron donor and PC61BM was the electron acceptor in the active layer. The device presented reasonable photovoltaic properties when the weight ratio of PBDTThQx:PC61BM reached 1:3. The open-circuit voltage, fill factor, and power conversion efficiency were gauged to be 0.75 V, 0.59, and 0.74%, respectively. The experimental data implied that PBDTThQx would be a promising donor candidate in the application of polymer solar cells. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40279.