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PUBLISHED ONLINE: 6 JULY 2014 | DOI: http://www.nature.com/doifinder/10.1038/nmat4014
Web End =10.1038/NMAT4014
Nam Joong Jeon1, Jun Hong Noh1, Young Chan Kim1, Woon Seok Yang1, Seungchan Ryu1
and Sang Il Seok1,2*
Organolead trihalide perovskite materials have been successfully used as light absorbers in ecient photovoltaic cells. Two dierent cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution-based process. We used CH3NH3 Pb(I1xBrx)3 (x=0.10.15) as the absorbing layer
and poly(triarylamine) as a hole-transporting material. The use of a mixed solvent of -butyrolactone and dimethylsulphoxide (DMSO) followed by toluene drop-casting leads to extremely uniform and dense perovskite layers via a CH3NH3IPbI2DMSO intermediate phase, and enables the fabrication of remarkably improved solar cells with a certied power-conversion eciency of 16.2% and no hysteresis. These results provide important progress towards the understanding of the role of solution-processing in the realization of low-cost and highly ecient perovskite solar cells.
Today, crystalline silicon dominates the solar panel industry but remains relatively expensive to manufacture. If devices could be fabricated from cheap materials by a simple solution
process without annealing at high temperature, their costs could be considerably reduced through mass production. Although dye-sensitized1, quantum dot2,3, organic4,5, and inorganicorganic heterojunction solar cells6,7 can be fabricated by multiple or single solution processes, the cells still suer from problems such as a lack of long-term stability and low conversion eciency due to fundamental energy losses associated with the extensive interface for charge separation. Recently, methylammonium lead halide (MAPbX3, where MA is methylammonium CH3NH3 and X is a halogen) perovskites816 have oered the promise of a breakthrough for next-generation solar devices. The use of perovskites aords several advantages: excellent optical properties that are tunable by managing chemical compositions13; ambipolar charge transport10; and very long electronhole diusion lengths17,18. Perovskite
materials have been applied as light absorbers to thin or thick mesoscopic metal oxides and planar heterojunction solar devices.For example, when MAPbI3 was loaded on a mesoporous (mp)-TiO2 electrode by the sequential deposition of PbI2 and methylammonium iodide (MAI), a 15.0% power-conversion eciency (PCE) was achieved under 1 sun illumination11. The
authors of ref. 12 reported a maximum performance...