Perovskites may be used for various thermoelectric applications

A Cornell-led team of scientists has discovered a crystalline material with ultralow thermal conductivity, which could lead to the design of novel energy conversion materials and devices.

After studying a popular hybrid perovskite and identifying the mechanisms for its low thermal conductivity, Zhiting Tian, assistant professor of mechanical and aerospace engineering at Cornell, turned her attention to a hybrid perovskite analogue, methylammonium bismuth iodide (CH3NH3)3Bi2I9, which she hypothesized would have an even lower thermal conductivity because of the unique disconnected structure of its inorganic molecules.

Addition of biological material boosts performance of perovskite solar cells

An international team of researchers, including ones from Penn State, Columbia University, University of Toledo, Northeastern University in the U.S and Carl von Ossietzky University in Germany, designed next-gen solar cells that mimic photosynthesis with a biological material, by adding the protein bacteriorhodopsin (bR) to perovskite solar cells.

Power conversion efficiency (PCE) distribution of bR-incorporated PSC imagePower conversion efficiency (PCE) distribution of bR-incorporated PSC based on statistics of 15 devices, with average efficiency of 16.34 %. Image from ACS article

“These findings open the door for the development of a cheaper, more environmentally friendly bioperovskite solar cell technology,” said Shashank Priya, associate vice president for research and professor of materials science at Penn State. “In the future, we may essentially replace some expensive chemicals inside solar cells with relatively cheaper natural materials.”

2D MXenes may improve perovskite solar cell efficiency

Researchers at the University of Rome Tor Vergata in Italy and Russia’s NUST MISIS institute have investigated how cells containing two-dimensional titanium-carbide MXene support layers could improve perovskite solar cell performance.

To obtain good power conversion within a perovskite solar cell, all layers and layer interfaces within the cell must have good compatibility. Typical cells contain the active perovskite material sandwiched between two charge transport layers, which are then adjacent to their corresponding electrodes. Support layers may also be added. Charge mobility, energy barriers, interface energy alignment, and interfacial vacancies all impact compatibility and subsequent cell performance and stability. Thus, engineering well-suited interfaces with the cell is paramount to cell success and long-term stability, an important criterion for potential commercialization.

Korean team uses a transparent conductive adhesive to combine perovskite and silicon solar cells

Researchers from the Ulsan Institute of Science and Technology (UNIST) have demonstrated a new method of fabricating perovskite-on-silicon tandem devices, using a transparent conductive adhesive (TCA) to combine the two cells. The scientists have developed devices with demonstrated efficiencies of 19.4%, and propose methods to bring that up to over 24% using existing technology.

While the efficiency is still well below the 28% record for a perovskite/silicon tandem cell set by Oxford PV, the UNIST group says its method is far simpler to manufacture than previous concepts. “It is meaningful to develop an attached tandem solar cell unlike the conventional tandem solar cell with stacked structure,” said UNIST’s In Young Choi, lead author of the study. “We have observed that the TCA effectively connects the different light-absorbing layers.”

HZB researchers reach 23.26% record efficiency for tandem perovskite-CIGS solar cell

A team led by Prof. Steve Albrecht from the HZB has announced a new world-record: a tandem solar cell with certified efficiency of 23.26% that combines the semiconducting materials perovskite and CIGS. One reason for this success lies in the cell’s intermediate layer of organic molecules: they self-organize to cover even rough semiconductor surfaces. Two patents have been filed for these layers.

World record for tandem perovskite-CIGS solar cell image

Perovskite-based solar cells have experienced an incredibly rapid increase in efficiency over the last ten years. The combination of perovskites with classical semiconductor materials such as silicon and copper-indium-gallium-selenide (CIGS) compounds in tandem solar cells promises low-cost, high-performance solar modules for the future. However, losses at the electrodes between the two semiconductors considerably reduce the efficiency.