Abstract The influence of the Schottky contact is studied for hole transport material (HTM) free
CH3NH3PbI3 perovskite solar cells (PSCs), by using drift-diffusion and small signal models. The basic
current-voltage and capacitance-voltage characteristics are simulated in reasonable agreement with experimental
data. The build in potential of the finite CH3NH3PbI3 layer is extracted from a Mott-Schottky
capacitance analysis. Furthermore, hole collector conductors with work-functions of more than 5.5 eV are
proposed as solutions for high efficiency HTM-free CH3NH3PbI3 PSCs.
influence_of_schottky_contact_on_the_c-v_and_j-v_characteristics.pdfChongwen Li, Yuanyuan Zhou, Yue Chang Li Wang, Yingxia Zong, Etgar Lioz, Guanglei Cui, Nitin P. Padture, and Shuping Pang. 5/19/2017. “
Methylammonium-Mediated Evolution of Mixed-Organic-CationPerovskite Thin Films: A Dynamic Composition-Tuning Process.” Angew. Chem. Int. Ed., 2017,56, Pp. 7674 –7678.
methylammonium.png methylammonium-mediated_evolution_of_mixed-organic-cation.pdf Yue Chang, Li Wang, Jiliang Zhang, Zhongmin Zhou, Chongwen Li, Bingbing Chen, Etgar Lioz, Guanglei Cui, and Shuping Pang. 2/10/2017. “
CH3NH2 gas induced (110) preferred cesiumcontainingperovskite films with reduced PbI6octahedron distortion and enhanced moisturestability.” J. Mater. Chem. A, 2017,5, Pp. 4803–4808.
Abstract We report here the discovery of a fancy interaction between cesium iodide (CsI) and methylamine (CH3NH2) due to the presence of the hydrogen bond. The formed CsI$xCH3NH2 is a liquid phase, which facilitates the large scale fabrication of highly uniform cesium-containing perovskite films with strong (110) preferred orientation by the CH3NH2 gas healing process. With this method, at most 10% nonpolar Cs cations could fully dope into the crystal lattice and extremely enhance the interaction of the inorganic framework with a more
symmetrical PbI6 octahedron, resulting in obvious improvement in moisture stability under continuous illumination.
An important property of hybrid layered perovskite is the possibility to reduce
its dimensionality to provide wider band gap and better stability. In this work,
2D perovskite of the structure (PEA)2(MA)n–1PbnBr3n+1 has been sensitized,
where PEA is phenyl ethyl-ammonium, MA is methyl-ammonium, and using
only bromide as the halide. The number of the perovskite layers has been
varied (n) from n = 1 through n = ∞. Optical and physical characterization
verify the layered structure and the increase in the band gap. The photovoltaic
performance shows higher open circuit voltage (Voc) for the quasi 2D perovskite
(i.e., n = 40, 50, 60) compared to the 3D perovskite. Voc of 1.3 V without
hole transport material (HTM) and Voc of 1.46 V using HTM have been
demonstrated, with corresponding efficiency of 6.3% and 8.5%, among the
highest reported. The lower mobility and transport in the quasi 2D perovskites
have been proved effective to gain high Voc with high efficiency, further
supported by ab initio calculations and charge extraction measurements. Bromide
is the only halide used in these quasi 2D perovskites, as mixing halides
have recently revealed instability of the perovskite structure. These quasi 2D
materials are promising candidates for use in optoelectronic applications that
simultaneously require high voltage and high efficiency.
