Low temperature dye-sensitized solar cells based on conformal thin zinc oxide overlayer on mesoporous insulating template by atomic layer deposition

Low temperature processing of dye-sensitized solar cells (DSCs) is essential to enable commercialization with low cost plastic substrates and diminish the overall manufacturing cost.We report a low temperature processing route for photoanodes where thin ZnO nanoshell is deposited by atomic layer deposition at 150°C, on a mesoporous insulating template. We found that a 6 nm ZnO overlayer on a 3 μm mesoporous nanoparticle Al2O3 template shows a power conversion efficiency of 4.2 % with the standard organic sensitizer (coded Y123) and cobalt bipyridine redox mediator

Time-dependent density functional theory study of squaraine dye-sensitized solar cells

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Electron donor-acceptor distance dependence of the dynamics of light-induced interfacial charge transfer in the dye-sensitization of nanocrystalline oxide semiconductors

The effect of electronic and nuclear factors on the dynamics of dye-to-semiconductor electron transfer was studied employing RuII(terpy)(NCS)3 sensitizers grafted onto transparent films made of titanium dioxide nanoparticles. Various approaches were strived to understand the dependence of the kinetics of charge injection and recombination processes upon the distance separating the dye molecules and the redox active surface. A series of bridged sensitizers containing p- phenylene spacers of various lengths and phosphonic anchoring groups were adsorbed onto TiO2 films. The kinetics of interfacial charge transfer was recorded by use of time-resolved spectroscopy in the fs-ps domain. The electron injection process was found to be biphasic with a clear exponential distance dependence of the fast kinetic component. The slower part of the kinetics was essentially unaffected by the length of the spacer bridge and was attributed to sensitizer molecules that are weakly bound to the surface with no direct contact of the anchoring group with the semiconductor. In a second approach, the kinetics of both forward- and back-electron transfer across a layer of insulating Al2O3 deposited onto TiO2 nanocrystalline particles was investigated. Efficient charge injection was observed over distances up to 3 nm

Migration of cations induces reversible performance losses over day/night cycling in perovskite solar cells

Perovskites have been demonstrated in solar cells with a power conversion efficiency of well above 20​%, which makes them one of the strongest contenders for next generation photovoltaics. While there are no concerns about their efficiency, very little is known about their stability under illumination and load. Ionic defects and their migration in the perovskite crystal lattice are some of the most alarming sources of degrdn., which can potentially prevent the commercialization of perovskite solar cells (PSCs)​. In this work, we provide direct evidence of elec. field-​induced ionic defect migration and we isolate their effect on the long-​term performance of state-​of-​the-​art devices. Supported by modeling, we demonstrate that ionic defects, migrating on timescales significantly longer (above 103 s) than what has so far been explored (from 10-​1 to 102 s)​, abate the initial efficiency by 10-​15​% after several hours of operation at the max. power point. Though these losses are not negligible, we prove that the initial efficiency is fully recovered when leaving the device in the dark for a comparable amt. of time. We verified this behavior over several cycles resembling day​/night phases, thus probing the stability of PSCs under native working conditions. This unusual behavior reveals that research and industrial stds. currently in use to assess the performance and the stability of solar cells need to be adjusted for PSCs. Our work paves the way for much needed new testing protocols and figures of merit specifically designed for PSCs

Certified high-efficiency "large-area" perovskite solar cells module for Fresnel lens-based concentrated photovoltaic

The future of energy generation is well in tune with the critical needs of the global economy, leading to more green innovations and emissions-abatement technologies. Introducing concentrated photovoltaic (CPV) is one of the most promising technologies owing to its high photo-conversion efficiency (PCE). While most researchers use silicon and cadmium telluride for CPV, we investigate the potential in nascent technologies, such as perovskite solar cell (PSC). This work constitutes a preliminary investigation into a ‘large-area’ PSC module under a Fresnel lens (FL) with a ‘refractive optical concentrator-silicon-on-glass’ base to minimise the PV performance and scalability trade-off concerning the PSCs. The FL-PSC system measured the solar current-voltage characteristics in variable lens-to-cell distances and illuminations. A systematic study of the PSC module temperature was monitored using the COMSOL transient heat transfer mechanism. The FL-based technique for ‘large-area’ PSC architecture is an unfolded technology that further facilitates the potential for commercialisation

Device Performance of Emerging Photovoltaic Materials (Version 3)

Following the 2nd release of the “Emerging PV reports,” the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2021. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application, and are put into perspective using, e.g., the detailed balance efficiency limit. The 3rd installment of the “Emerging PV reports” extends the scope toward triple junction solar cells

Device Performance of Emerging Photovoltaic Materials (Version 3)

Following the 2nd release of the “Emerging PV reports,” the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2021. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application, and are put into perspective using, e.g., the detailed balance efficiency limit. The 3rd installment of the “Emerging PV reports” extends the scope toward triple junction solar cells

Device Performance of Emerging Photovoltaic Materials (Version 2)

Following the 1st release of the “Emerging photovoltaic (PV) reports”, the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2020. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application and are put into perspective using, e.g., the detailed balance efficiency limit. The 2nd instalment of the “Emerging PV reports” extends the scope toward tandem solar cells and presents the current state-of-the-art in tandem solar cell performance for various material combinations.</p

Device Performance of Emerging Photovoltaic Materials (Version 1)

Emerging photovoltaics (PVs) focus on a variety of applications complementing large scale electricity generation. Organic, dye‐sensitized, and some perovskite solar cells are considered in building integration, greenhouses, wearable, and indoor applications, thereby motivating research on flexible, transparent, semitransparent, and multi‐junction PVs. Nevertheless, it can be very time consuming to find or develop an up‐to‐date overview of the state‐of‐the‐art performance for these systems and applications. Two important resources for recording research cells efficiencies are the National Renewable Energy Laboratory chart and the efficiency tables compiled biannually by Martin Green and colleagues. Both publications provide an effective coverage over the established technologies, bridging research and industry. An alternative approach is proposed here summarizing the best reports in the diverse research subjects for emerging PVs. Best performance parameters are provided as a function of the photovoltaic bandgap energy for each technology and application, and are put into perspective using, e.g., the Shockley–Queisser limit. In all cases, the reported data correspond to published and/or properly described certified results, with enough details provided for prospective data reproduction. Additionally, the stability test energy yield is included as an analysis parameter among state‐of‐the‐art emerging PVs