No abstract

Semitransparent organic solar cells (STOSCs) are of great interest in both academic and industrial fields since they can be easily used as building windows to achieve solar power generation in building façades.

Organic solar cells (OSCs) are considered to have reached a second golden age with profoundly improved power conversion efficiency (PCE) and device stability in recent years. The modification of the interface layer plays a significant role in achieving performance enhancement in OSCs. Herein, the use of the atomic layer deposition (ALD) ultrathin TiOx to modify the interface layer in OSCs is reported. The modification with only two TiOx ALD cycles not only effectively passivates the interface between the ZnO electron transport layer (ETL) and the active layer, but also reduces the series resistance and improves the charge transport process in the device. An absolute 1% increase in PCE with enhanced device stability for modified OSCs is achieved. Semitransparent OSCs are also fabricated by applying this interface modification strategy. The modification with two TiOx ALD cycles increases the electrical device performance without affecting the optical properties of the semitransparent device. An average PCE of 10.46% with an average visible transmittance (AVT) of 19.61% and a color rendering index (CRI) close to 100 is demonstrated for the fabricated semitransparent device with the modification. The ALD‐assisted interface modification provides a straightforward way to realize high‐performance semitransparent OSCs.

Organic solar cells (OSCs) are promising photovoltaic devices and zinc oxide (ZnO) is a commonly used electron transport layer (ETL) in OSCs. However, the conventional spin-coating ZnO layer is currently limiting its efficiency potential. Herein, it is shown for the first time that atomic layer deposition (ALD), which allows for controlled thin film growth with atomic-scale control, can effectively be used to optimize the ZnO for nonfullerene OSCs. First, density functional theory (DFT) calculations are discussed to show the impact of doping ZnO with zirconium (Zr) on its density of states and detail the synthesis of Zr doped ZnO films by ALD using a supercycle approach. A 2.4% Zr concentration is found to be optimal in terms of optoelectronic properties and sufficiently low defect density. The champion efficiency of 14.7% for a PM6:N3-based nonfullerene OSC with Zr-doped ZnO ETL are obtained, which is %1% absolute higher compared to a device with an undoped ZnO ETL. This improvement is attributed to a lower series resistance, a suppressed surface recombination, and an enhanced current extraction resulting from the Zr-doped ZnO. This work demonstrates the potential of atomic-scale engineering afforded by ALD towards achieving the ultimate efficiency of OSCs.

The industry for producing silicon solar cells and modules has grown remarkably over the past decades, with more than a 100-fold reduction in price over the past 45 years. The main solar cell fabrication technology has shifted over that time and is currently dominated by the passivated emitter and rear cell (PERC). Other technologies are expected to increase in market share, including tunnel-oxide passivated contact (TOPCon) and heterojunction technology (HJT). In this paper, we examine the cost potential for using atomic layer deposition (ALD) to form transition metal oxide (TMO) layers (MoO x , TiO x and aluminium-doped zinc oxide [AZO]) to use as lower cost alternatives of the p-doped, n-doped and indium tin oxide (ITO) layers, respectively, the layers normally used in HJT solar cells. Using a bottom-up cost and uncertainty model with equipment cost data and process experience in the lab, we find that the production cost of these variations will likely be lower per wafer than standard HJT, with the main cost drivers being the cost of the ALD precursors at highvolume production. We then considered what efficiency is required for these sequences to be cost effective in $/W and discuss whether these targets are technically feasible. This work motivates further work in developing these ALD TMO processes to increase their efficiency towards their theoretical limits to take advantage of the processing cost advantage.