Highly Efficient Indoor Organic Photovoltaics with Spectrally Matched Fluorinated Phenylene‐Alkoxybenzothiadiazole‐Based Wide Bandgap Polymers

Abstract

The unique electro‐optical features of organic photovoltaics (OPVs) have led to their use in applications that focus on indoor energy harvesters. Various adoptable photoactive materials with distinct spectral absorption windows offer enormous potential for their use under various indoor light sources. An in‐depth study on the performance optimization of indoor OPVs is conducted using various photoactive materials with different spectral absorption ranges. Among the materials, the fluorinated phenylene‐alkoxybenzothiadiazole‐based wide bandgap polymer—poly[(5,6‐bis(2‐hexyldecyloxy)benzo[c][1,2,5]thiadiazole‐4,7‐diyl)‐alt‐(5,50‐(2,5‐difluoro‐1,4‐phenylene)bis(thiophen‐2‐yl))] (PDTBTBz‐2Fanti)‐contained photoactive layer—exhibits a superior spectrum matching with indoor lights, particularly a light‐emitting diode (LED), which results in an excellent power absorption ratio. These optical properties contribute to the state‐of‐the‐art performance of the PDTBTBz‐2Fanti:[6,6]‐phenyl‐C71 butyric acid methyl ester (PC71BM)‐based OPV with an unprecedented high power‐conversion efficiency (PCE) of 23.1% under a 1000 lx LED. Finally, its indoor photovoltaic performance is observed to be better than that of an interdigitated‐back‐contact‐based silicon photovoltaic (PCE of 16.3%).

Vacuum‐Deposited Transparent Organic Photovoltaics for Efficiently Harvesting Selective Ultraviolet and Near‐Infrared Solar Energy

“…In the previous work, we have demonstrated that the vacuum‐deposited OPV can exhibit a PCE close to 16% under a TLD‐840 fluorescent lamp (800 lux; 0.232 mW cm −2 ), [ 73 ] which might indicate that new energy‐harvesting technology can convert the environmental or sunlight energy efficiently to drive low‐power‐consumption electronics. [ 74 ] Several materials and systems, such as OPVs, [ 53,54,75 ] dye‐sensitized solar cells, [ 76 ] polymer solar cells, [ 77–79 ] and perovskite PVs [ 80,81 ] have been used to achieve high‐efficiency self‐sustainable power in the past 3 years. [ 82 ] Here, we propose that the TPV module developed in this work can directly charge a homemade LiFePO 4 (LFP) battery (CR2032 coin cell; Figure S13, Supporting Information) with a capacity of 0.58 mAh under the sunlight.…”

Indoor application of emerging photovoltaics—progress, challenges and perspectives

“…1a and Table 1). 27 However, for fullerene-based blend systems, there is limited potential to further enhance the V oc value since the energy level of the fullerene acceptor cannot easily be adjusted and only the energy level of the polymer donor can be tuned. Nonfullerene acceptors (NFAs), on the other hand, offer more opportunities to deliver higher V oc due to more adjustable properties of both the donor and acceptor.…”

Nonfullerene Small Molecules‐Enabled High‐Performance Organic Photovoltaics for Indoor Energy Harvesting

“…A combination of mid-bandgap polymers and [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 70 BM) is widely studied active layer components, which match the indoor light illuminance mostly lying in the visible wavelength region between 400 and 700 nm. [8][9][10] By contrast, state-of-the-art nonfullerene acceptors have received only minor consideration until recently. This is because their bandgap (E g ) values are relatively small to match the indoor light spectrum, whereas such low E g materials play critical roles in securing the harvest of broadband photons under solar irradiation.…”