Photoluminescence and photo-induced conductivity in 2D siloxene nanosheet for optoelectronic applications

Semiconducting 2D siloxene nanosheets of thickness 1.7 nm and band gap of 2.54 eV are synthesized using simple chemical route. Strong photoluminescence is observed in the as-synthesized nanosheets due to presence of oxygen atoms. The photoluminescence behaviour of siloxene nanosheets is investigated by controlling temperature, excitation and pH of the solution to understand the optical response and stability of the material. The as-synthesized sample heated with temperature 200 °C shows a blue shift of 90 nm compared to the sample synthesized at room temperature. The low temperature luminescence measurements of as-synthesized samples dried at different temperatures viz. 27, 100 and 200 °C. It is seen that the luminescence intensity is increasing with decreasing temperature for the sample dried at room temperature. However, after heating the sample at 100 °C, the luminescence intensity is not only increased but also red-shifted up to 52 nm. The photocurrent has been measured for the device structure of ITO/PEDOT: PSS/Siloxene/Al with different film thicknesses to optimize the photocurrent and the maximum percentage change in photo power gain. The maximum photopower gain of 2693% is observed for the film thickness of 600 nm.