Application of a c‐Si Solar Cell with a Three‐Dimensional Structure to Indoor Photovoltaics

Abstract

are considerably weaker sources of illumination compared to sunlight.Unfortunately, most PV devices are optimized for outdoor use, having the ability to generate electric power on the order of watts to gigawatts (e.g., power plants) with sunlight exposure. [14] The crystalline silicon (c-Si) solar cell has been widely used under sunlight, as it is economical, expandable, and capable of being mass-produced. [15][16][17] However, artificial light sources have low light intensity and a narrow spectrum, residing mostly in the visible light regime (400-700 nm). As such, indoor photovoltaics (IPV) such as amorphous silicon (a-Si) solar cells, dyesensitized solar cells (DSSCs), perovskite solar cells (PSCs), and organic photovoltaics (OPVs) are often used indoors, as these types of PVs have the necessary absorption spectra and high energy conversion efficiency under weak lighting conditions. [10,[18][19][20][21][22] In contrast, the c-Si solar cell has low electrical power output due to its broad absorption spectrum and linearly decreasing power output under reduced light intensity. [23][24][25] However, as large-sized cells or modules, most of the abovementioned PV types have degradation problems, with the exception of the c-Si solar cell. Despite degradation under ambient light, the c-Si solar cell has the advantages of high durability and expandability for IPV applications. [26][27][28] In this study, we attempted to overcome the low energy conversion characteristics of a c-Si solar cell under weak lighting conditions, using a three-dimensional (3-D) configuration to acquire more indirect light, as well as direct light for increased power generation from the PV device. Compared to sunlight, artificial light sources, such as indoor lighting, tend to be fairly weak as the light is more diffuse and scattered. If the artificial light sources are installed periodically, as in an office setting, for example, the indirect light portion is increased. Incident daylight enters through windows at various angles (angled incident light). The energy generated from direct light is related to the occupied area assuming that the power density of the cells is constant. However, the total surface area is the most important factor when using indirect light. Here, we introduce a 3-D c-Si solar cell configuration to increase the total surface area for light accumulation from various angles, with a similar footprint to its flat cell counterpart.To fabricate the 3-D solar cell, we replaced the window glass, the ethylene vinyl acetate (EVA) film, and the metal frame of a conventional module with polydimethylsiloxane (PDMS) and an epoxy back frame. In our previous study, we demonstrated As individual photovoltaic (PV) power sources for indoor conditions, various types of solar cells including organic, perovskite, and dye-sensitized devices, have been used because they provide better performance under weak lighting conditions; however, they are limited in terms of durability and applicability to larger-sized cells and modules. Crystalline sili...

Electric power from shadows and indoors: solar cells under diffuse light conditions

“…Unlike photovoltaics deployed outdoors, indoor photovoltaics operate with low-intensity and dispersed light sources. 13,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]70 In general, the indoor light intensity is less than 1/100th the intensity of sunlight. The spectrum also differs from that of sunlight and depends on the kind of lighting.…”

Indoor organic solar cells for low-power IoT devices: recent progress, challenges, and applications

“…22,[28][29][30][31][32] Interestingly, recent studies have shown that emerging photovoltaic technologies such as perovskite solar cells (PSCs), [33][34][35] OSCs, 25,28,36 and dye-sensitized solar cells (DSSCs) [37][38][39] are better for converting indoor light into electricity than other inorganic Si, CIGS technologies. [40][41][42] This is due to a broader range of optical tunability, a higher absorption coefficient, and smaller leakage currents at low light intensities. 7,[43][44][45][46] For example, the PSCs had a PCE of 37.2% under 6500 K LED illumination (1000 lux) with ambient stability of more than 800 hours reported, as by Noh and workers.…”

Doping-Free High-Performance Photovoltaic Effect in a WSe2 Lateral p-n Homojunction Formed by Contact Engineering

“…For applications in devices such as photovoltaics, photodetectors, and light-emitting diodes, group III–V direct band gap semiconductors and bulk Si are widely used in conventional diode structures. − However, these materials lack flexibility and transparency and have low optical absorption coefficients, limiting their applications in flexible devices like solar cells or transparent displays. − Unlike ordinary semiconductors, there has been considerable interest in the utilization of two-dimensional (2D) layered materials, such as transition metal dichalcogenides (TMDs), for the fabrication of high-performance PV devices. − TMDs exhibit advantageous photovoltaic properties owing to their wide range of band gaps, indicating the wavelengths of light that the materials can absorb and convert into energy.…”