Semitransparent Thin Film Solar Cells using Cu-doped Bi2(S,Se)3 Nanocrystals for Building-Integrated Photovoltaics

EPA Grant Number: SU839290
Title: Semitransparent Thin Film Solar Cells using Cu-doped Bi2(S,Se)3 Nanocrystals for Building-Integrated Photovoltaics
Investigators: Das, Sandip
Institution: Kennesaw State University
EPA Project Officer: Page, Angela
Phase: I
Project Period: February 1, 2018 through January 31, 2019
Project Amount: $14,977
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2017) RFA Text |  Recipients Lists
Research Category: P3 Awards , Sustainability , P3 Challenge Area - Energy


Development of low-cost and mass deployable solar photovoltaic (PV) technology is crucial to realize solar power as the primary source of renewable energy for a sustainable future, mitigation of environmental impacts by reducing greenhouse and toxic gas emissions, and meeting the global demand of terawatt-scale PV power generation predicted by 20301,2. Building-Integrated Photovoltaics (BIPV) is expected to be the major contributor in solar power generation3-5. The current commercial solar cell technology is based on silicon (Si) which makes the solar modules rigid, fragile, and heavy. In addition, these heavy modules pose significant logistical issues and incur extra cost requiring expensive mechanical structures to mount them onto buildings. Due to such serious drawbacks, installation of solar panels have been limited to the building rooftops only, which severely restricts the power generation capacity due to limited roof surface area available. Thus, development of new light-weight, portable, and flexible solar photovoltaic technology is of utmost importance which can mitigate the above mentioned issues and address the sustainability challenges by easy retrofitting/building-integration of the solar modules.


The proposed P3 research program aims to develop novel nano-structured solar cells by applying potentially transformative and disruptive nanotechnology resulting in lightweight, semi-transparent, flexible thin film solar cells that can be easily retrofitted onto windows, rooftops, and even the vertical walls of a building – thus substantially increasing the PV power generation capacity and improve energy efficiency by reducing the space cooling requirements.


By engineering the optical bandgap of light-absorbing Bi2(S,Se)3 nanocrystals and embedding them onto infrared-sensitive polymers, our solar cells will primarily absorb the invisible near-UV and near-infrared (NIR) spectrum of the sunlight while remaining optically transparent to the visible light. By easily retrofitting these cells onto existing windows of a building, the energy generation capacity can be increased up to two times for a two-storied building and multi-fold for a skyscraper without affecting the aesthetics or the visible light transmission through the windows. A further increase in power generation capacity can be achieved by mounting these light-weight solar modules on the outside walls. In addition to power generation, the retrofitted modules will substantially reduce the space cooling requirements by absorbing heat producing infrared radiation. The research program will heavily involve and educate at least four undergraduate students and engage several high-school students. The project represents an ideal blend of scientific research, engineering design, and community engagement. The end result of the project promises a significant leap forward toward improved sustainability resulting in economic development – thus meeting the goals of the people, prosperity, and the planet (P3) program.

Expected Results:

We aim to fabricate thin film hybrid solar cells using Cu-doped Bi2(S,Se)3 semiconductor nanocrystals and infrared-sensitive organic polymers. Solar cells will be fabricated onto plastic substrates leading to flexible and semi-transparent modules suitable for windows and BIPV applications. The specific objective of this project (phase I) is to fabricate prototype working solar cells showing the viability of the proposed technology that promises to achieve cell efficiencies of ~10% at less than half the cost of Si solar cells. By developing lightweight, flexible solar technology suitable for BIPV applications, the innovation promises to improve energy efficiency of buildings and increase the photovoltaic power generation capacity, thus reducing the dependence on fossil fuels and mitigate the greenhouse and toxic gas emissions into the atmosphere. Through scientific innovation and engineering applications, this project will be a transformational model for the future research in renewable and sustainable energy technologies.

The nanocrystal synthesis, solar cell fabrication and characterization methods in the proposed work will ideally suit the schedule of undergraduate students and instill the necessary skills to pursue a research career in the field of sustainable/renewable energy. The project will address fundamental questions of nanocrystal synthesis, thin film preparation and device fabrication with a broader impact of training and involving undergraduate students in a comprehensive manner. Students will get hands-on experience in experiment design, device fabrication, characterization, photovoltaic efficiency evaluation and scientific communication that will facilitate their career in the engineering, material science, and nanotechnology related fields. This proposal will improve our fundamental understanding of the doping process at the nano-scale, the effects of anion composition variation in Bi2(S,Se)3 nanocrystals (and in general V2-VI3 compounds) and their resulting photovoltaic properties. The innovative materials system and the device design would lead to a light-weight, portable solar technology for building-integrated photovoltaic applications.

Supplemental Keywords:

Photovoltaic technology, renewable energy, alternative energy source, energy conservation, nanotechnology