| 초록 |
We report polymeric hole transport material (HTM) with dopant-free, which exhibits highly stable and efficient perovskite solar cells (∼17.3% for over 1400 h at 75% humidity). The HTM consisted of a random copolymer (RCP), which is characterized using UV-vis spectrophotometer, cyclic voltammetry, space-charge-limited current, and grazing-incidence wide-angle X-ray scattering (GIWAXS). The RCP-based perovskite solar cell shows the highest efficiency (17.3%) in the absence of dopants [lithium bis(trifluoromethanesulfonyl)imide and tert-butylpyridine]. The observed efficiency is resulted from a deep HOMO energy level and high hole mobility. In addition, the long-term stability of the device is dramatically improved by avoiding deliquescent or hygroscopic dopants and by introducing a hydrophobic polymer layer. RCP devices maintain their initial efficiency for over 1400 h at 75% humidity, whereas devices made of HTMs with additives fail after 900 h. |
