Present solar cells are expensive making photovoitaic electricity only attractive whenever there is government incentive. This paper highlights the cost of photovoltaic classified according to first, second and third ...Present solar cells are expensive making photovoitaic electricity only attractive whenever there is government incentive. This paper highlights the cost of photovoltaic classified according to first, second and third generations. The first and second generations make up the current photovoltaic. The reasons for the efficiency limitation of the first and second generation photovoltaic are given. Nanoparticles such as quantum dots have confinement properties that can be exploited to improve solar cell efficiency and help reduce the cost. Quantum effect that support hot electron collection and multiple exciton generation through impact ionization are discussed. These form the basis of the future generation quantum dot solar cell.展开更多
Luminescent solar concentrators（LSC） can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic（PV） cells, and thereby red...Luminescent solar concentrators（LSC） can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic（PV） cells, and thereby reducing the cost of PV electricity generation. LSCs with bottom-facing cells（BMP-LSC） can collect both direct light and indirect light, so further improving the efficiency of the PV cells. However, it is hard to analyze the effect of each parameter by experiment because there are too many parameters involved in the BMP-LSC. In this paper, all the physical processes of the light transmission and collection in the BMP-LSC were analyzed. A three-dimensional Monte Carlo ray tracing program was developed to study the transmission of photons in the LSC. A larger-size LSC was simulated, and the effects of dye concentration, the LSC thickness, the cell area, and the cell distance were systematically analyzed.展开更多
A new mechanism of light-to-electricity conversion that uses InGaN/GaN QWs with a p-n junction is reported.According to the well established light-to-electricity conversion theory,quantum wells（QWs） cannot be used i...A new mechanism of light-to-electricity conversion that uses InGaN/GaN QWs with a p-n junction is reported.According to the well established light-to-electricity conversion theory,quantum wells（QWs） cannot be used in solar cells and photodetectors because the photogenerated carriers in QWs usually relax to ground energy levels,owing to quantum confinement,and cannot form a photocurrent.We observe directly that more than 95% of the photoexcited carriers escape from InGaN/GaN QWs to generate a photocurrent,indicating that the thermionic emission and tunneling processes proposed previously cannot explain carriers escaping from QWs.We show that photoexcited carriers can escape directly from the QWs when the device is under working conditions.Our finding challenges the current theory and demonstrates a new prospect for developing highly efficient solar cells and photodetectors.展开更多
文摘Present solar cells are expensive making photovoitaic electricity only attractive whenever there is government incentive. This paper highlights the cost of photovoltaic classified according to first, second and third generations. The first and second generations make up the current photovoltaic. The reasons for the efficiency limitation of the first and second generation photovoltaic are given. Nanoparticles such as quantum dots have confinement properties that can be exploited to improve solar cell efficiency and help reduce the cost. Quantum effect that support hot electron collection and multiple exciton generation through impact ionization are discussed. These form the basis of the future generation quantum dot solar cell.
基金Project supported by the National Natural Science Foundation of China(Grant No.U1632273)the Chinese Universities Scientific Fund(Grant No.CX3430000001)
文摘Luminescent solar concentrators（LSC） can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic（PV） cells, and thereby reducing the cost of PV electricity generation. LSCs with bottom-facing cells（BMP-LSC） can collect both direct light and indirect light, so further improving the efficiency of the PV cells. However, it is hard to analyze the effect of each parameter by experiment because there are too many parameters involved in the BMP-LSC. In this paper, all the physical processes of the light transmission and collection in the BMP-LSC were analyzed. A three-dimensional Monte Carlo ray tracing program was developed to study the transmission of photons in the LSC. A larger-size LSC was simulated, and the effects of dye concentration, the LSC thickness, the cell area, and the cell distance were systematically analyzed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574362,61210014,and 11374340)the Innovative Clean-energy Research and Application Program of Beijing Municipal Science and Technology Commission,China(Grant No.Z151100003515001)
文摘A new mechanism of light-to-electricity conversion that uses InGaN/GaN QWs with a p-n junction is reported.According to the well established light-to-electricity conversion theory,quantum wells（QWs） cannot be used in solar cells and photodetectors because the photogenerated carriers in QWs usually relax to ground energy levels,owing to quantum confinement,and cannot form a photocurrent.We observe directly that more than 95% of the photoexcited carriers escape from InGaN/GaN QWs to generate a photocurrent,indicating that the thermionic emission and tunneling processes proposed previously cannot explain carriers escaping from QWs.We show that photoexcited carriers can escape directly from the QWs when the device is under working conditions.Our finding challenges the current theory and demonstrates a new prospect for developing highly efficient solar cells and photodetectors.
