Researchers at the Centre for Hybrid and Organic Solar Energy (CHOSE), Department of Electronic Engineering University of Rome – Tor Vergata, in collaboration with researchers at the Department of Physics and Astronomy and London Centre for Nanotechnology at University College London, have developed perovskite solar cells with maximum power density under white LED illumination of 20.2 µW/cm2 at 200 lx and 41.6 µW/cm2 at 400 lx (corresponding to a power conversion of 27%).
The authors of the work believe these to be the highest power output densities ever reported under illumination conditions typically found in homes and offices. The exceptional performance under indoor lighting was achieved by incorporating new solution-processed SnO2/MgO composite electron transport layers between the perovskite semiconductor film and the bottom transparent electrode. The thin MgO overlayer enhances efficiency by 20%, reducing charge recombination which is especially important at the low light levels typically found indoors.
All layers of the cells, except for the two electrodes, were solution processed at low temperatures, making the technology easy to integrate with other printed electronic components on the same substrate, and compatible with low cost manufacturing. Ambient indoor conditions represent a milder environment compared to stringent outdoor conditions suggesting an initial commercial outlet which is much less taxing on device lifetimes for this technology.
Thus, the researchers suggest that the unparalleled performance demonstrated, furnishes these devices with another new powerful competitive attribute that can pave the way for perovskite solar cells to contribute strongly to energy harvesting and the powering of the indoor electronics of the future (e.g. the fast-rising markets of autonomous indoor wireless sensor networks and the internet of things).
Perovskite solar cells have been attracting great attention from the scientific and industrial communities in the past few years because they are able to combine high power conversion efficiencies under standard test conditions (i.e. those of the sun) with simple manufacturing processes. The films that make up the cells are in fact cast from solution (i.e. printed via inks) or evaporated over large areas.
Source: CHOSE and UCL
Results have recently been published in Nano Energy.
Highly efficient perovskite solar cells for light harvesting under indoor illumination via solution processed SnO2/MgO composite electron transport layers
Janardan Dagar | Sergio Castro-Hermosa | Giulia Lucarelli | Franco Cacialli | Thomas M.Brown
Nano Energy | Available online 12 April 2018 | In Press
https://doi.org/10.1016/j.nanoen.2018.04.027
Highlights
- New architectures in CH3NH3PbI3 based planar perovskite solar cells incorporating solution processed SnO2/MgO composite electron transport layers.
- Cells shows highest power outputs ever reported under typical 200–400 lx indoor illumination conditions.
- When measured under white OSRAM LED lamp (200, 400 lx), the maximum power density values were 20.2 µW/cm2 (estimated PCE = 25.0%) at 200 lx and 41.6 µW/cm2 (PCE = 26.9%) at 400 lx which correspond to a ∼ 20% increment compared to solar cells with a SnO2 layer only.
- The maximum power conversion efficiency was 19.0% under 1 sun illumination of the best cell with a stabilized value of 18.1%.
- All layers of the cells, except for the two electrodes, are solution processed at low temperatures, thus low cost processing.
- The thin MgO overlayer leads to more uniform films, reduces interfacial carrier recombination, and leads to better stability.
- Furthermore, ambient indoor conditions represent a milder environment compared to stringent outdoor conditions for a technology that is still looking for a commercial outlet also due to stability concerns.
Abstract
We present new architectures in CH3NH3PbI3 based planar perovskite solar cells incorporating solution processed SnO2/MgO composite electron transport layers that show the highest power outputs ever reported under typical 200–400 lx indoor illumination conditions. When measured under white OSRAM LED lamp (200, 400 lx), the maximum power density values were 20.2 µW/cm2 (estimated PCE = 25.0%) at 200 lx and 41.6 µW/cm2 (PCE = 26.9%) at 400 lx which correspond to a ∼ 20% increment compared to solar cells with a SnO2 layer only. The thin MgO overlayer leads to more uniform films, reduces interfacial carrier recombination, and leads to better stability. All layers of the cells, except for the two electrodes, are solution processed at low temperatures, thus low cost processing. Furthermore, ambient indoor conditions represent a milder environment compared to stringent outdoor conditions for a technology that is still looking for a commercial outlet also due to stability concerns. The unparalleled performance here demonstrated, paves the way for perovskite solar cells to contribute strongly to the powering of the indoor electronics of the future (e.g. smart autonomous indoor wireless sensor networks, internet of things etc).