Researchers at Shaanxi Normal University in China have developed an organic-inorganic hybrid perovskite solar cell that uses 2D perovskite crystal as the template for 3D perovskite growth. In the recent study, the team developed a seed-mediated method to in situ grow a layer of 2D perovskite seed for epitaxial growth of 3D perovskite atop it, to construct a high-quality 2D/3D heterojunction.
It was reportedly found that the epitaxial 3D perovskite film exhibited a preferred direction, which is different from traditional perovskites with a preferred orientation. The oriented perovskite film consists of large-sized grains with low defect density, long charge-carrier lifetime and good stability, resulting in efficient PSCs with a champion efficiency of 24.83%.
In addition, the devices were said to exhibit high stability under ambient, thermal, and continuous light-soaking conditions. This work provides an effective strategy for achieving high-quality perovskite films with tunable orientation to simultaneously boost the efficiency and stability of PSCs.
The scientists built the cell with a 2D/3D heterojunction architecture. The device features a substrate made of tin oxide (FTO), a titanium oxide (TiO2) electron transport layer, a perovskite layer deposited on diaminobenzidine (DAB) film via spin coating, a spiro-OMeTAD hole transport layer, and a metal contact.
The researchers said the DAB film can modify the morphology of the perovskite films. “DAB modification on the bottom and top surfaces of the perovskite film can significantly passivate and reduce defects, thus reducing nonradiative recombination loss in the perovskite film,” they explained.
The solar cell has a power conversion efficiency of 24.83%, an open-circuit voltage of 1.19 V, a short-circuit current of 25.21 mA cm−2, and a fill factor of 82.61%.
“The unencapsulated devices maintain 95% and 89% of their initial efficiency after storing in ambient air for 1,650 hours or heating at 85 C for 500 hours, respectively, and the encapsulated device sustains 88% of its initial PCE after MPP tracking for 200 h under continuous illumination,” said the research group.
