Doped SnO2 nanoparticles for solar-cell application

Since conventional TiO2 electron transporting layer (ETL) can accelerate the degradation of organic lead halide perovskite solar cells, alternative ETL is required for PSCs with extended lifetime. In this work, SnO2 nanoparticles, a potential ETL material, were synthesized via facile sol-gel method. Different dopants were introduced in an attempt to enhance conductivity and improve electronic properties of pristine SnO2. The prepared nanoparticles were identified to be rutile SnO2 phase with crystalline size less than 4 nm. The presence of the dopant in the doped samples was confirmed by energy dispersive X-ray spectroscopy, and it is also evident from the colour change of the doped samples compared to undoped one. While the dopant incorporation has been successful, nanoparticles exhibited pronounced aggregation in water dispersions, which prevented preparation of sufficiently smooth films for application in planar perovskite solar cells. Further optimization of the nanoparticle surfaces is needed to obtain dispersions suitable for spin-coating uniform thin films of doped SnO2.