What is a perovskite solar cell?
Perovskite solar cells are a type of compound thin-film solar cell that uses perovskite-type materials as the light-absorbing layer. Perovskite solar cells use perovskite-type organic metal halide semiconductors as the light-absorbing material.
Perovskite is not specifically referring to a compound containing calcium and titanium, but rather a general term for a class of crystal materials with an ABX3 structure, with many possible material options.
The structure of perovskite solar cells mainly consists of the following key components: transparent conductive substrate, electron transport layer, perovskite light-absorbing layer, hole transport layer, and metal electrode. These components work together to efficiently absorb sunlight and convert it into electrical energy.
Transparent conductive substrate: This is the foundation of the perovskite solar cell, usually made from materials like fluorine-doped tin oxide (FTO) or indium-doped tin oxide (ITO), which have high transparency and good conductivity. Its main role is to introduce sunlight and collect the generated current. The choice of transparent conductive substrate is crucial for the performance of perovskite solar cells, as it not only affects the light incident angle but also the extraction of the generated current.
Electron transport layer: Located between the transparent conductive substrate and the perovskite light-absorbing layer, its primary function is to transport electrons. Common materials used for electron transport layers include titanium dioxide (TiO2) and zinc oxide (ZnO), which have good electron mobility and stability, capable of transporting electrons generated in the perovskite light-absorbing layer to the transparent conductive substrate.
Perovskite light-absorbing layer: This is the core part of the perovskite solar cell, mainly composed of organic halide perovskite materials with an ABX3 structure. These materials have excellent optoelectronic conversion performance, effectively converting solar energy into electrical energy. The preparation process and properties of the perovskite light-absorbing layer are decisive for the overall performance of the perovskite solar cell.
Hole transport layer: Located between the perovskite light-absorbing layer and the metal electrode, its main function is to transport holes. Common materials for hole transport layers include Spiro-OMeTAD, which can effectively extract and transport photogenerated holes, thereby improving the cell's optoelectronic conversion efficiency.
Metal electrode: This is the final layer of the perovskite solar cell, mainly responsible for transporting charges and connecting the external circuit. Typically, a layer of gold, silver, or aluminum is deposited on top of the hole transport layer to enhance the conductivity of the electrode.
The structure of perovskite solar cells can vary, with each structure having its unique features and applications. Common structures include mesoporous, planar, and inverted planar configurations.