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Semi-transparent (ST) solar cells are attracting a lot of attention among researchers as they can effectively utilize solar energy in various fields such as building-integrated solar power generation and portable solar chargers. Here, we introduce an ST solar cell composed of triethylenetetramine (TETA)-doped graphene (Gr), WS2, and LaVO3. The device not only harvests solar energy thanks to its high light absorption in the ultraviolet-visible range but is also translucent due to its thin film composition. The photovoltaic parameters and average visible transmittance (AVT) of TETA-Gr/WS2/LaVO3 solar cells are highly dependent on the LaVO3 film thickness (t). Considering the correlation between efficiency and visual effects, the device has power conversion efficiency (PCE) of 5.07% and 35% AVT at t = 200 nm, suggesting that it is suitable for ST solar cells. To maximize the translucent properties of the device, the PCE of the device was further improved to 5.64% by using an Al reflective mirror. The durability of the cell was confirmed to maintain 91 and 84% of the original PCE even under continuous illumination of 1 Sun at 60 °C temperature (Ta) and 30% relative humidity (RH) and 80 °C Ta/50% RH for 1000 h. [ABSTRACT FROM AUTHOR]

High-density pores formed on Si are effective for enhancing the light absorption of Si, thereby improving the efficiency of graphene (GR)/Si-heterojunction optoelectronic devices. Insulating hexagonal boron nitride (h-BN) is highly attractive as an interfacial material between GR and semiconducting materials for heterostructures because of the large bandgap/small lattice mismatch with GR. Here, we first report the bifunctional enhancement of photodetection and photovoltaic parameters in (trifluoromethanesulfonyl)-amide-doped GR (TFSA-GR)/porous Si (PSi)/Si heterostructures by employing a h-BN interlayer at the TFSA-GR/PSi interface and a bathocuproine (BCP) passivation layer on the Si back surface. The concurrent use of h-BN and BCP layers makes it difficult for the electrons to overcome the energy barriers as well as for the photo-induced electrons/holes to be recombined at the interfaces, thereby decreasing the dark current (DC) and facilitating the photocarrier collection, respectively. These effects result in remarkable improvements of the photoresponse and energy harvesting. In particular, the specific detectivity is almost 100 times enhanced at zero bias, i.e., under self-powered. The devices also show excellent long-term stability by maintaining 98 and 74% of their original photocurrent and DC, respectively, when kept in air for 2000 h. These results suggest that TFSA-GR/h-BN/PSi/Si/BCP heterostructures are very promising for application in self-powered or self-driving multifunctional optoelectronic devices. [ABSTRACT FROM AUTHOR]

Formation of pores on Si wafer as an effective approach to enhance the light absorption of Si is attractive for graphene (GR)-based-heterojunction optoelectronic devices such as GR/porous Si (PSi) photodetectors (PDs), but the misalignment at the GR/PSi interface limits further enhancement of the PDs' performance. Here, we first employ WS2 as an interfacial layer between GR and PSi to fabricate GR/WS2/PSi heterojunction PDs exhibiting a broad-band photoresponse in the visible range, originating from the enlarged band gap of PSi based on the quantum confinement effect. By the insertion of the WS2 interfacial layer, the PDs' parameters including responsivity, detectivity, and external quantum efficiency are greatly improved under reverse bias due to the increased built-in field throughout the device, resulting in better separation of the photoinduced electron–hole pairs. In addition, the response time of the PDs shows a sharp decrease in the GR/WS2/PSi structure compared to the GR/WS2/Si counterpart (102/228 → 2.46/1.16 μs for the rise/fall times in the transient photocurrent curve). A 20% loss of the responsivity value is observed after the stability of the PDs is tested during 2000 h in air, resulting from the passivation of WS2 for the GR and PSi surfaces. [ABSTRACT FROM AUTHOR]

A heterostructure composed of a combination of semi-metallic graphene (Gr) and high-absorption LaVO3 is ideal for high-performance translucent photodetector (PD) applications. Here, we present multilayer Gr/LaVO3 vertical-heterostructure semitransparent PDs with various layer numbers (L n ). At L n = 2, the PD shows the best performance with a responsivity (R) of 0.094 A Wâˆ'1 and a specific detectivity (D *) of 7.385 × 107 cm Hz1/2 Wâˆ'1 at 532 nm. Additionally, the average visible transmittance of the PD is 63%, i.e. it is semitransparent. We increased photocurrent (PC) by approximately 13%, from 0.564 to 0.635 ÎĽ A cmâˆ'2 by using an Al reflector on the semitransparent PD. The PC of an unencapsulated PD maintains about 86% (from 0.571 to 0.493 ÎĽ A cmâˆ'2) of its initial PC value after 2000 h at 25 °C temperature/30% relative humidity, showing good stability. This behavior is superior to that of previously reported graphene-based PDs. These results show that these PDs have great potential for semitransparent optoelectronic applications. [ABSTRACT FROM AUTHOR]

Semitransparent solar cells are attracting attention not only for their visual effects but also for their ability to effectively utilize solar energy. Here, we demonstrate a translucent solar cell composed of bis(trifluoromethane sulfonyl)-amide (TFSA)-doped graphene (Gr), graphene quantum dots (GQDs), and LaVO 3 . By introducing a GQDs intermediate layer at the TFSA-Gr/LaVO 3 interface, we can improve efficiency by preventing carrier recombination and promoting charge collection/separation in the device. As a result, the efficiency of the GQDs-based solar cell was 4.35%, which was higher than the 3.52% of the device without GQDs. Furthermore, the average visible transmittance of the device is 28%, making it suitable for translucent solar cells. The Al reflective mirror-based system improved the power conversion efficiency by approximately 7% compared to a device without a mirror. Additionally, the thermal stability of the device remains at 90% even after 2000 h under an environment with a temperature of 60 °C and 40% relative humidity. These results suggest that TFSA-Gr/GQDs/LaVO 3 -based cells have a high potential for practical use as a next-generation translucent solar energy power source., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Two-dimensional (2D) semiconductor and LaVO 3 materials with high absorption coefficients in the visible light region are attractive structures for high-performance photodetector (PD) applications. Insulating 2D hexagonal boron nitride (h-BN) with a large band gap and excellent transmittance is a very attractive material as an interface between 2D/semiconductor heterostructures. We first introduce WS 2 /h-BN/LaVO 3 semitransparent PD. The photo-current/dark current ratio of the device exhibits a delta-function characteristic of 4 × 10 5 at 0 V, meaning 'self-powered'. The WS 2 /h-BN/LaVO 3 PD shows up to 0.27 A W -1 responsivity ( R ) and 4.6 × 10 10 cm Hz 1/2 W -1 detectivity ( D *) at 730 nm. Especially, it was confirmed that the D * performance improved by about 5 times compared to the WS 2 /LaVO 3 device at zero bias. Additionally, it is suggested that the PD maintains 87% of its initial R for 2000 h under the atmosphere with a temperature of 25 °C and humidity of 30%. Based on the above results, we suggest that the WS 2 /h-BN/LaVO 3 heterojunction is promising as a self-powered optoelectronic device., (© 2024 IOP Publishing Ltd.)