@article {1116, title = {Performance and Limits of 2.0 eV Bandgap CuInGaS2 Solar Absorber Integrated With CdS Buffer on F:SnO2 Substrate for Multijunction Photovoltaic and Photoelectrochemical Water Splitting Devices}, volume = {2}, year = {2021}, pages = {5752-5763}, doi = {https://doi.org/10.1039/D1MA00570G}, author = {N. Gaillard and W. Septina and J. Varley and T. Ogitsu and K. K. Ohtaki and H. A. Ishii and J. P. Bradley and C. Muzzillo and K. Zhu and F. Babbe and J. Cooper} } @article {990, title = {Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations}, journal = {Journal of Applied Physics}, volume = {123}, year = {2018}, note = {

{\textquoteright}doi: 10.1021/acsenergylett.0c01132\n - I.Am.Hydrogen{\textquoteright} {\textquoteright}\n - jyoungstrom{\textquoteright} {\textquoteright}Jason thinks this is great.\n\ \n - jyoungstrom{\textquoteright} {\textquoteright}\n - estechel{\textquoteright}

}, pages = {161408}, abstract = {

Publshed on March 7th, 2018. Understanding the impact of impurities in solar absorbers is critical to engineering high-performance in devices, particularly over extended periods of time. Here, we use hybrid functional calculations to explore the role of hydrogen interstitial (Hi) defects in the electronic properties of a number of attractive solar absorbers within the chalcopyrite and kesterite families to identify how this common impurity may influence device performance. Our results identify that Hi can inhibit the highly p-type conditions desirable for several higher-band gap absorbers and that H incorporation could detrimentally affect the open-circuit voltage (Voc) and limit device efficiencies. Additionally, we find that Hi can drive the Fermi level away from the valence band edge enough to lead to n-type conductivity in a number of chalcopyrite and kesterite absorbers, particularly those containing Ag rather than Cu. We find that these effects can lead to interfacial Fermi-level pinning that can qualitatively explain the observed performance in high-Ga content CIGSe solar cells that exhibit saturation in the Voc with increasing band gap. Our results suggest that compositional grading rather than bulk alloying, such as by creating In-rich surfaces, may be a better strategy to favorably engineering improved thin-film photovoltaics with larger-band gap absorbers.

}, issn = {0021-8979}, doi = {10.1063/1.5006272}, url = {https://aip.scitation.org/doi/10.1063/1.5006272}, author = {J. B. Varley and V. Lordi and T. Ogitsu and A. Deangelis and K. Horsley and N. Gaillard} }