Graphene-Templated Achiral Hybrid Perovskite for Circularly Polarized Light Sensing.

This study points out the importance of the templating effect in hybrid organic-inorganic perovskite semiconductors grown on graphene. By combining two achiral materials, we report the formation of a chiral composite heterostructure with electronic band splitting. The effect is observed through circularly polarized light emission and detection in a graphene/α-CH(NH)PbI perovskite composite, at ambient temperature and without a magnetic field.

Infrared-reflective ultrathin-metal-film-based transparent electrode with ultralow optical loss for high efficiency in solar cells.

In this work we study in-depth the antireflection and filtering properties of ultrathin-metal-film-based transparent electrodes (MTEs) integrated in thin-film solar cells. Based on numerical optimization of the MTE design and the experimental characterization of thin-film perovskite solar cell (PSC) samples, we show that reflection in the visible spectrum can be strongly suppressed, in contrast to common belief (due to the compact metal layer). The optical loss of the optimized electrode (~ 2.

Metal Halide Perovskites for High-Energy Radiation Detection.

Metal halide perovskites (MHPs) have emerged as a frontrunner semiconductor technology for application in third generation photovoltaics while simultaneously making significant strides in other areas of optoelectronics. Photodetectors are one of the latest additions in an expanding list of applications of this fascinating family of materials. The extensive range of possible inorganic and hybrid perovskites coupled with their processing versatility and ability to convert external stimuli into easily measurable optical/electrical signals makes them an auspicious sensing element even for the high-energy domain of the electromagnetic spectrum.

Efficient and environmental-friendly perovskite solar cells via embedding plasmonic nanoparticles: an optical simulation study on realistic device architectures.

Solution-processed, lead halide-based perovskite solar cells have recently overcome important challenges, offering low-cost and high solar power conversion efficiencies. However, they still undergo unoptimized light collection due mainly to the thin (∼350 nm) polycrystalline absorber layers. Moreover, their high toxicity (due to the presence of lead in perovskite crystalline structures) makes it necessary that the thickness of the absorber layers to be further reduced.

Inorganic and Hybrid Perovskite Based Laser Devices: A Review.

Inorganic and organic-inorganic (hybrid) perovskite semiconductor materials have attracted worldwide scientific attention and research effort as the new wonder semiconductor material in optoelectronics. Their excellent physical and electronic properties have been exploited to boost the solar cells efficiency beyond 23% and captivate their potential as competitors to the dominant silicon solar cells technology. However, the fundamental principles in Physics, dictate that an excellent direct band gap material for photovoltaic applications must be also an excellent light emitter candidate.

Graphene-Based Inverted Planar Perovskite Solar Cells: Advancements, Fundamental Challenges, and Prospects.

Metal halide based perovskite solar cells (PSCs) are considered among the most promising photovoltaic technologies, and already present certified efficiencies that surpass 22 %. The high performance and low fabrication cost make this technology competitive with that of state-of-the-art thin-film photovoltaics. However, PSCs present some striking disadvantages that hinder their commercialization, including short operational lifetimes, high toxicity, and hysteresis effects, which lower both the performance and long-term stability of the devices.

Solution Processed CHNHPbICl Perovskite Based Self-Powered Ozone Sensing Element Operated at Room Temperature.

Hybrid lead halide spin coated perovskite films have been successfully tested as portable, flexible, operated at room temperature, self-powered, and ultrasensitive ozone sensing elements. The electrical resistance of the hybrid lead mixed halide perovskite (CHNHPbICl) sensing element, was immediately decreased when exposed to an ozone (O) environment and manage to recover its pristine electrical conductivity values within few seconds after the complete removal of ozone gas. The sensing measurements showed different response times at different gas concentrations, good repeatability, ultrahigh sensitivity and fast recovery time.

Improved Carrier Transport in Perovskite Solar Cells Probed by Femtosecond Transient Absorption Spectroscopy.

CHNHPbI perovskite thin films have been deposited on glass/indium tin oxide/hole transport layer (HTL) substrates, utilizing two different materials as the HTLs. In the first configuration, the super hydrophilic polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), known as PEDOT:PSS, was employed as the HTL material, whereas in the second case, the nonwetting poly(triarylamine) semiconductor polymer, known as PTAA, was used. It was found that when PTAA is used as the HTL material, the averaged power conversion efficiency (PCE) of the perovskite solar cells (PSCs) remarkably increases from 12.

Size-Tuning of WSe Flakes for High Efficiency Inverted Organic Solar Cells.

The development of large-scale production methods of two-dimensional (2D) crystals, with on-demand control of the area and thickness, is mandatory to fulfill the potential applications of such materials for photovoltaics. Inverted bulk heterojunction (BHJ) organic solar cell (OSC), which exploits a polymer-fullerene binary blend as the active material, is one potentially important application area for 2D crystals. A large ongoing effort is indeed currently devoted to the introduction of 2D crystals in the binary blend to improve the charge transport properties.

Solution processed reduced graphene oxide electrodes for organic photovoltaics.

Since the isolation of free standing graphene in 2004, graphene research has experienced a phenomenal growth. Due to its exceptional electronic, optical and mechanical properties, graphene is believed to be the next wonder material for optoelectronics. The enhanced electrical conductivity, combined with its high transparency in the visible and near-infrared regions of the spectrum, enabled graphene to be an ideal low cost indium-tin oxide (ITO) substitute.

Enhanced Stability of Aluminum Nanoparticle-Doped Organic Solar Cells.

Enhancement of the stability of bulk heterojunction (BHJ) organic photovoltaic (OPV) devices is reported by the addition of surfactant-free aluminum (Al) nanoparticles (NPs) into the photoactive layer. The universality of the effect is demonstrated for two different BHJ systems, namely, the well-studied poly(3-hexylthiophene-2,5-diyl):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) as well as the high efficient poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]:[6,6]-phenyl-C71-butyric acid methyl ester (PCDTBT:PC71BM). It is shown that the lifetime of the devices with Al NPs, operating under continuous one-sun illumination in ambient conditions, is more than three times longer compared to the reference devices.

Synergetic plasmonic effect of Al and Au nanoparticles for efficiency enhancement of air processed organic photovoltaic devices.

Enhancement in the efficiency of air processed bulk heterojunction photovoltaic devices is demonstrated via the addition of highly stable uncapped gold (Au) and aluminum (Al) nanoparticles (NPs) into the photoactive layer. An enhancement in conversion efficiency by 15% is observed, which can be attributed to Localised Surface Plasmon Resonance effects at the small diameter Au NPs and to efficient scattering by the large diameter Al NPs.