OPTIMIZING A MULTI-TIO2 BASED ELECTRON TRANSPORT LAYER FOR PEROVSKITE SOLAR CELLS

The purpose of this paper is to manufacture perovskite solar cells (PSC) employing an TiO2 electron transport layer that consists of two different TiO2 particles. Anatase TiO2 nanoparticles with the dimensions of similar to 5 nm were synthesized at a low temperature using dimethylformamide as a structure directing agent. Hydrolysis of TiCl4 and subsequent TiO2 crystal growth were controlled without using conventional hydrothermal methods. Ethanol based nanofluids containing a mixture of commercial anatase TiO2 particles with the dimensions of 20 nm and the tiny TiO2 particles were prepared to create the multi-TiO2 based electron transport layer. In first step for the device assembly, a buffer layer (compact TiO2 layer) was spin-coated and subsequently sintered to stabilize particles on FTO glass. Secondly, the newly prepared TiO2 nanofluid was deposited, using spin coater technique and sintered to form the electron transport layer. The light absorber Perovskite and Spiro-OMeTAD (hole transport material) were successively deposited with a spin-coater in a glove box at a humidity of less than 20 %. Finally, a gold layer was deposited on top of the Spiro-OMeTAD. A systematical change of the ratio of adding different size TiO2 particles was examined to optimize the anatase TiO2 electron transport layer in PSC. In addition, the characteristics of other deposited layers were also optimized to maximize the efficiency of PSC. The device performance of PSC was tested under 1 sun light condition using a solar simulator.