Bingwei Luo

Synergistic photovoltaic-thermoelectric effect in a nanostructured CdTe/Bi2Te3 heterojunction for hybrid energy harvesting

Recent advances in the photovoltaic and thermoelectric material synthesis and characterization have engendered significant interest in their solar energy harvesting. However, examples of energy harvesting by the two effects in one single cell are relatively rare, and at present there are no known examples to solve the heat problem in a conventional solar cell. Here we show that a synergistic photovoltaic and thermoelectric effect takes place in a single heterojunction solar cell that consists a p-type CdTe nanorod array and n-type Bi2Te3 nanostructures. This novel cell is capable of converting light and heat into electricity via combined photovoltaic and thermoelectric processes, providing a simple and elegant material structure for development of high efficiency solar cells which can harvest solar energy over a wider solar spectrum. In addition, this discovery may provide a viable solution to the heat problems in conventional solar cells. Based on the synergistic photovoltaic and thermoelectric effect, the cell of FTO/CdS/CdTe/Bi2Te3 has been prepared and an efficiency (η) increase of 23.3% is achieved after 1 min illumination

Enhanced adhesion and conductivity of Cu electrode on AlN substrate for thin film thermoelectric device

The Cu thin film electrode grown on aluminum nitride (AlN) substrate is widely used in the thin film thermoelectric devices due to its high electrical conductivity. We have developed a new type of buffer layer by co-sputtering Ti and Cu forming Ti–Cu layer. The Ti–Cu layer was sputtered on the Ti buffered AlN substrate so that the adhesion and electrical conductivity properties of the Cu film electrode on AlN substrate could be improved. The interface between the thin films and the substrate were characterized by the scanning electron microscope (SEM). Nanoscratch tests were conducted on a nanomechanical test system to investigate the adhesion between the Cu film electrodes and AlN substrate. Meanwhile, accelerated ageing test under thermal cycling was conducted to evaluate the reliability of the thin film electrode. The results show that the adhesion and the reliability of Cu film electrode on AlN substrate have been greatly improved by employing Ti–Cu/Ti buffer layers.

Influence of Cu on Transport Properties of Thermoelectric Thin Film Fabricated via Magnetron Co-sputtering Method: Influence of Cu on Transport Properties of Thermoelectric Thin Film Fabricated via Magnetron Co-sputtering Method

A simple magnetron co-sputtering method was used to fabricate Cu dispersed Bi0.5Sb1.5Te3 thin films, and the co-sputtering method was beneficial to the preferential growth of Bi0.5Sb1.5Te3 thin films along c-axis. Cu atoms were well-dispersed in the nano-structured materials. The electrical conductivity sharply increased with the increasing content of Cu due to the effect of Cu on transport property. For Cu target sputtering power of 20 W, a maximum power factor of 20 μW/(cm⋅K) with an electrical conductivity of 15 × 10 S/m at 355 K were achieved.

PHOTOELECTRODE WITH LIGHT AND HEAT SYNERGY UTILIZATION BASED ON CdTe/Bi2Te3 NANOROD ARRAYS/NANOLAYER FILM

Photoelectrode of CdTe/Bi2Te3 nanorod arrays/nanolayer film is designed for light and heat synergy utilization, which is carried out by two-step synthesis route of magnetron sputtering. The composition and microstructure of CdTe/Bi2Te3 nanorod arrays/nanolayer are determined by powder X-ray diffraction and scanning electron microscopy. Under AM 1.5 G illumination, the power conversion efficiency of CdTe/Bi2Te3 nanorod arrays/nanolayer photoelectrode is 10 times larger than that of CdTe nanorod arrays. It was found that the power conversion efficiency is mainly affected by the thickness of the Bi2Te3 film. These results significantly improve the performance of low-dimension CdTe photoelectrochemical solar cells and also open new possibilities for solar light and heat synergy utilization.