Li Yue, Fu Jun, Mao Xiaoyu, Chen Chen, Liu Heng, Gong Ming, Zeng Hualing
International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Science at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, 230026, Hefei, Anhui, People's Republic of China.
Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Department of Physics, University of Science and Technology of China, 230026, Hefei, Anhui, People's Republic of China.
Nat Commun. 2021 Oct 8;12(1):5896. doi: 10.1038/s41467-021-26200-3.
The photocurrent generation in photovoltaics relies essentially on the interface of p-n junction or Schottky barrier with the photoelectric efficiency constrained by the Shockley-Queisser limit. The recent progress has shown a promising route to surpass this limit via the bulk photovoltaic effect for crystals without inversion symmetry. Here we report the bulk photovoltaic effect in two-dimensional ferroelectric CuInPS with enhanced photocurrent density by two orders of magnitude higher than conventional bulk ferroelectric perovskite oxides. The bulk photovoltaic effect is inherently associated to the room-temperature polar ordering in two-dimensional CuInPS. We also demonstrate a crossover from two-dimensional to three-dimensional bulk photovoltaic effect with the observation of a dramatic decrease in photocurrent density when the thickness of the two-dimensional material exceeds the free path length at around 40 nm. This work spotlights the potential application of ultrathin two-dimensional ferroelectric materials for the third-generation photovoltaic cells.
光伏中的光电流产生主要依赖于p-n结或肖特基势垒的界面，其光电效率受肖克利-奎塞尔极限的限制。最近的进展表明，对于没有反演对称性的晶体，通过体光伏效应有一条超越这一极限的有前景的途径。在此，我们报道了二维铁电体CuInPS中的体光伏效应，其光电流密度比传统的体铁电钙钛矿氧化物提高了两个数量级。体光伏效应与二维CuInPS中的室温极性有序本质上相关。我们还展示了从二维到三维体光伏效应的转变，当二维材料的厚度超过约40nm处的自由程长度时，观察到光电流密度急剧下降。这项工作突出了超薄二维铁电材料在第三代光伏电池中的潜在应用。
