• Energy Research

Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels 200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments.

Concentrator photovoltaics achieve high efficiency but have so far been impractical for use on rooftops. Here, Price et al. develop a flat-panel concentrating photovoltaic system based on a triple-junction solar cell that operates at fixed tilt over a full day with…

AbstractA new design for microtracked concentrating photovoltaics (mCPVs) published by one of us in Nature Energy has the same form factor as PV. This paper analyzes the cost below which it would compete with PV in behind‐the‐meter applications for commercial electricity customers in four cities in southern United States, assuming that the only significant differences between mCPV and PV are mCPV's higher efficiency and mCPV's inability to utilize sunlight that is either diffuse or has a high angle of incidence. The analysis first optimizes PV and mCPV microgrids and then selects the battery capacity that maximizes the internal rate of return (IRR) and selects a target mCPV installed cost for which the optimal mCPV IRR matches the optimal PV IRR. The result for projects starting in 2020 is $1.2/W in Lancaster, CA and Las Vegas, cities with similar ratios of direct to total irradiance. Modesto, CA and Kansas City have target mCPV installed costs of $1.07/W and $0.94/W, respectively. The electricity tariff and battery costs impact both PV and mCPV and have a minimal effect on the mCPV cost at which the two technologies compete. mCPV occupies 33.2% less area per watt than PV reducing some components of installed cost. In 2020, target mCPV module costs are $0.33/W in Lancaster and Las Vegas, $0.25/W in Modesto, and $0.17/W in Kansas City. These target costs decline by on average 9.6% per year for projects starting 2021–2025, similar to the 9.3% rate of decline in projected PV module costs over this period.

A novel solid-state design is presented for an organic intermediate band solar cell with electrically integrated triplet–triplet annihilation upconversion.

Fair and meaningful device per- formance comparison among luminescent solar concentrator- photovoltaic (LSC-PV) reports cannot be realized without a gen- eral consensus on reporting stan- dards in LSC-PV research. There- fore, it is imperative to adopt standardized characterization protocols for these emerging types of PV devices that are consistent with other PV devices. This commentary highlights several common limitations in LSC literature and summarizes the best practices moving for- ward to harmonize with standard PV reporting, considering the greater nuances present with LSC-PV. Based on these prac- tices, a checklist of actionable items is provided to help stan- dardize the characterization/re- porting protocols and offer a set of baseline expectations for au- thors, reviewers, and editors. The general consensus combined with the checklist will ultimately guide LSC-PV research towards reliable and meaningful ad- vances.

Dye-sensitized solar cells (DSSCs) differ from conventional solar cells in that they rely on a large area nanoparticle network to achieve sufficient absorption of sunlight. Although highly successful to date, this approach limits the opportunities to further increase DSSC power efficiency because it necessarily restricts the choice of redox shuttles to those compatible with the long electron transit times and ample recombination opportunities inherent to the nanoparticle-based architecture. Here, we use a resonantly coupled cavity scheme to demonstrate planar, thin-film DSSCs with a polarized, monochromatic incident photon to current efficiency of 17% from a single monolayer of a conventional Ru-dye. Upon illumination on resonance we observe open-circuit voltages that reach 1 V and thereby approach the theoretical limit for open-circuit voltage set by the dye and redox shuttle energy levels. The results supply new insight into processes presently limiting DSSCs and point to novel strategies to overcome these losses.