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We study the structural development of complex soft materials to elucidate their processing-structure-function relationships for optoelectronics and energy applications.

Research Spotlight

Highly Transparent, Scalable, and Stable Perovskite Solar Cells with Minimal Aesthetic Compromise

Transparent photovoltaics (TPVs) can be integrated into the surfaces of buildings and vehicles to provide point-of-use power without impacting aesthetics. Unlike TPVs that target the photon-rich near-infrared portion of the solar spectrum, TPVs that harvest ultraviolet (UV) photons can have significantly higher transparency and color neutrality, offering a superior solution for low-power electronics with stringent aesthetic tolerance. In addition to being highly transparent and colorless, an ideal UV-absorbing TPV should also be operationally stable and scalable over large areas while still outputting sufficient power for its specified application. None of today's TPVs meet all these criteria simultaneously. Here, the first UV-absorbing TPV is demonstrated that satisfies all four criteria by using CsPbCl2.5Br0.5 as the absorber. By precisely tuning the halide ratio during thermal co-evaporation, high-quality large-area perovskite films can be accessed with an ideal absorption cutoff for aesthetic performance. The resulting TPVs exhibit a record average visible transmittance of 84.6% and a color rendering index of 96.5, while maintaining an output power density of 11 W m−2 under one-sun illumination. Further, the large-area prototypes up to 25 cm2 are demonstrated, that are operationally stable with extrapolated lifetimes of >20 yrs under outdoor conditions.

Perovskite Solar Cells: Extending the Photovoltaic Response of Perovskite Solar Cells into the Near‐Infrared with a Narrow‐Bandgap Organic Semiconductor

We demonstrate a near‐infrared‐harvesting perovskite solar cell with enhanced power‐conversion efficiency as high as 21.6% and improved stability, with an operational half‐life of 1900 h, by directly incorporating a multifunctional organic semiconductor that both extends light absorption and passivates defects in the perovskite active layers. This work provides a promising approach to prepare highly efficient and stable perovskites solar cells and opens a new application field for the rational design of narrow‐bandgap organic semiconductors.

Assessing the Huang-Brown Description of Tie Chains for Charge Transport in Conjugated Polymers

Tie chains electrically bridge crystalline domains in semiconducting polymers, effectively reducing interdomain resistance and improving charge transport. In this work, we quantified the tie-chain fraction through a classical polymer–physics framework and established the percolation threshold for charge transport in poly(3-hexylthiophene)s.

Pairing of Near-UV Solar Cells with Electrochromic Windows for Smart Management of the Solar Spectrum

The various wavelengths of the solar spectrum can be exploited for different functionalities. We have developed an organic solar cell that harvests near-ultraviolet photons to power an electrochromic device that controls how many photons go through a smart window in other wavelength ranges, adjusting both visible light and heat ingress.

Research Spotlight archive

News

Tianran's article on "Highly Transparent, Scalable, and Stable Perovskite Solar Cells with Minimal Aesthetic Compromise" has been featured on the cover of Advanced Energy Materials.

Monday, September 04, 2023

Tianran Liu successfully defends his Ph.D. Congratulations and good luck Dr. Liu!

Tuesday, May 09, 2023

Elizabeth Wall, CBE, joins the group as a graduate student - welcome!

Thursday, February 02, 2023

Xiaoming Zhao published in Science a perovskite solar cell with record breaking stability, and an accelerated testing method that allows quantification. Check out the press release. Congratulations!

Thursday, June 16, 2022

News archive