New approach for understanding temperature effects on photovoltaic device performance

Phys.org  June 14, 2023 Little is known about the operational temperature which is critical in a solar cell’s ability to convert sunlight to free energy. Researchers in Israel analyzed the photovoltaic effect while assuming a fixed ambient temperature and a varying system temperature rather than using the standard fixed system temperature–based approaches. They studied the potential-dependent current and temperature of solar cells and thermoradiative power generators and showed that the optimal band gap of a solar cell depends on its heat-transfer coefficient and that its efficiency may rise or fall as solar concentration increases, depending on its ability to dissipate […]

How one photon becomes four charge carriers

Phys.org  April 14, 2023 In a usual solar cell, the energy of a single photon is transferred to two free charges in the material. However, a few molecular materials like pentacene are an exception and show conversion of one photon into four charges, instead. This excitation doubling, which is called exciton fission, could be extremely useful for high-efficiency photovoltaics, specifically to upgrade the dominant silicon-based technologies. An international team of researchers (Germany, Canada) used time- and angle-resolved photoemission spectroscopy to observe the primary step of singlet fission in crystalline pentacene. Their results indicated a charge-transfer mediated mechanism with a hybridization […]

Solar harvesting system has potential to generate solar power 24/7

Science Daily  October 3, 2022 Traditional solar thermophotovoltaics (STPVs) rely on an intermediate layer to tailor sunlight for better efficiencies. However, the thermodynamic efficiency limit of STPVs is still far lower than the Landsberg limit (93.3%), the ultimate efficiency limit for solar energy harvesting. Researchers at the University of Houston showed that the efficiency deficit is caused by the back emission of the intermediate layer towards the sun resulting from the reciprocity of the system. They proposed nonreciprocal solar thermophotovoltaics (NSTPV) that utilize an intermediate layer with nonreciprocal radiative properties. Such a nonreciprocal intermediate layer could substantially suppress its back […]

Photovoltaics: Fully scalable all-perovskite tandem solar modules

Science Daily  July 14, 2022 Researchers in Germany have developed a prototype for fully scalable all-perovskite tandem solar modules which have an efficiency of up to 19.1 percent with an aperture area of 12.25 square centimeters. The improved efficiency was realized with optimized light paths, high-throughput laser scribing, and the use of established industrial coating methods. Perovskite solar cells with a tunable band gap are ideal tandem partners for solar cells made of other materials and for all-perovskite tandem solar cells. They were able to scale up individual perovskite cells with an efficiency of up to 23.5 percent .They feature […]

Perovskite photovoltaics for a greener Internet-of-Things

Nanowerk  April 28, 2022 An international team of researchers (UK, USA – City College of New York) reviewed the novel device concepts that comprise photovoltaic cells alone or in tandem with batteries or supercapacitors, acting as the main power supply to another microelectronic component, enabling self-powered electronics for the Internet of Things (IoT). They emphasize the specific requirements posed by such applications to pave the way to large scale commercialization. They highlighted the importance of supporting a greener IoT ecosystem by eliminating toxic materials and solvents in the device fabrication process…read more. Open Access TECHNICAL ARTICLE 

Daylight damage to photovoltaics

Science Daily  December 2, 2019 The cumulative damage from the sun tends to erode efficiency of a new class of solar cells that utilizes layers of carbon-based polymers. Based on the results of current-voltage curves, impedance spectroscopy, and UV-VIS spectrophotometry, researchers in Japan have determined that exposure to the sun’s ultraviolet light can damage the fragile organic molecules in the semiconducting layer just like it damages human skin. When some sulfur atoms in the materials get replaced by oxygen atoms from the atmosphere, the molecules no longer function as intended. The degradation products from solar damage increased the electrical resistance […]