Solar energy is one of the most promising energy supply channels in the future. The most promising method of utilizing solar energy is solar cells that can converse solar energy into electricity. Therefore, developing new solar cells has become a hot topic. Perovskite solar cells (PSC) that use metal-organic halides as light absorbing materials were firstly reported in 2009, which has the advantages of high photoelectric conversion efficiency and low cost. When sunlight irradiates the perovskite solar cells (PSC), perovskite absorbs photons and produces electron hole pairs, inducing the transformation of electrons from the valence band to the conduction band. Then, the electrons move to the conduction band of the electron transport layer. The electrons introduce the carriers into the external circuit through the current gathering effect of the conductive film in the anode and circulate back to the opposite electrode, thus forming electric current.
Figure 1. The structure picture of perovskite solar cell (PSC).
- Transportation field: In transportation field, a variety of signaling lights require power. Perovskite solar cells (PSC) are applied in navigation lights, railway signals, sign lights, high-altitude obstacle lights, railway wireless telephone booths and the others.
- Communications field: Perovskite solar cells (PSC) are also widely used in communications field，such as solar unattended microwave relay station, optical cable maintenance station, small communication machine, communication power system and the others.
- Construction field: Perovskite solar cells (PSC) combing with building materials is a major development direction, which will make large buildings self-sufficient in electricity in the future.
- The others: Perovskite solar cells (PSC) also have promising application prospects in meteorological fields, power supply for household lamps, photovoltaic power station and electric cars.
Perovskite solar cells (PSC) are made of many materials, the most important materials are light absorbing materials, hole transport layer materials and electron transport layer materials.
- Light absorbing materials: The light absorbing material of perovskite solar cell is perovskite material which has high mobility and low carrier recombination rate.
Figure 2. Structure unit diagram of perovskite material.
- Hole transport layer materials: The materials of hole transport layer can be divided into organic hole transport layer materials and inorganic hole transport layer materials. Organic hole transport layer materials include Spiro-OMeTAD, PEDOT:PSS, and P3HT. Inorganic hole-transporting materials mainly include NiO, CuI, CuSCN, Cu2O, CuO, MoOx and carbon materials. Among them, carbon materials include graphene and carbon nanotubes.
Figure 3. The molecular structure of Spiro-OMeTAD.
- Electron transfer layer materials: Electron transfer layer materials can be divided into metal oxide electron transport material and organic small molecule electron transport materials. TiO2 is the most representative of metal oxide electron transport materials. In addition, the most common organic small molecule electron transport materials are fullerenes and their derivatives.
Figure 4. Chemical structure of fullerene and its derivatives.
- Green M A, Ho-Baillie A, Snaith H J. The emergence of perovskite solar cells[J]. Nature Photonics, 2014, 8(7):506-514.
- Kojima A, Teshima K, Shirai Y, et al. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells.[J]. Journal of the American Chemical Society, 2009, 131(17):6050-6051.