Photovoltaic materials: Present efficiencies and future challenges

Polman, A.; Knight, Mark W.; Garnett, Erik C.; Ehrler, Bruno; Sinke, W.C.

doi:10.1126/science.aad4424

Cited by 1,772 publications

(1,378 citation statements)

References 39 publications

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“…Cu 2 ZnSnS 4 has a similar Urbach energy and has a V OC 0.5 V below its Shockley-Queisser limit value. [46,50] Band tails and sub-bandgap states present in the NiO x ( Figure S43, Supporting Information) and ZnO layers (measured previously, [45,51] and from Figure S42, Supporting Information) can also lead to V OC losses due to carrier thermalization or recombination from the band tails. [45,52] Further device modeling and temperature-dependent V OC measurements are required to quantify the magnitudes of these different effects.…”

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confidence: 68%

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Strongly Enhanced Photovoltaic Performance and Defect Physics of Air‐Stable Bismuth Oxyiodide (BiOI)

et al. 2017

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Bismuth‐based compounds have recently gained increasing attention as potentially nontoxic and defect‐tolerant solar absorbers. However, many of the new materials recently investigated show limited photovoltaic performance. Herein, one such compound is explored in detail through theory and experiment: bismuth oxyiodide (BiOI). BiOI thin films are grown by chemical vapor transport and found to maintain the same tetragonal phase in ambient air for at least 197 d. The computations suggest BiOI to be tolerant to antisite and vacancy defects. All‐inorganic solar cells (ITO|NiOx|BiOI|ZnO|Al) with negligible hysteresis and up to 80% external quantum efficiency under select monochromatic excitation are demonstrated. The short‐circuit current densities and power conversion efficiencies under AM 1.5G illumination are nearly double those of previously reported BiOI solar cells, as well as other bismuth halide and chalcohalide photovoltaics recently explored by many groups. Through a detailed loss analysis using optical characterization, photoemission spectroscopy, and device modeling, direction for future improvements in efficiency is provided. This work demonstrates that BiOI, previously considered to be a poor photocatalyst, is promising for photovoltaics.

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confidence: 68%

“…[46] One factor possibly limiting the V OC is nonradiative recombination due to shunt pathways or limited carrier collection (as discussed above). From the J-V curves of our devices, we estimated the shunt resistance to be 230 Ω cm 2 under 1 sun illumination (Figure 3f).…”

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confidence: 99%

Strongly Enhanced Photovoltaic Performance and Defect Physics of Air‐Stable Bismuth Oxyiodide (BiOI)

et al. 2017

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“…112 When a Rashba or Dresselhaus effect is observed on the valence and/or conduction band one can expect effect on the lifetime of the carriers. Indeed, it has been proposed that the band splitting resulting of these effects would enhance the lifetime of charge carriers because of spin-forbidden transitions 113 and the resulting A c c e p t e d m a n u s c r i p t indirect band gap.…”

Section: Effect On Carrier Lifetimementioning

confidence: 99%

Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Képénékian

Even

2017

J. Phys. Chem. Lett.

165

181

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In halide hybrid organic-inorganic perovskites (HOP), spin-orbit coupling (SOC) presents a well-documented large influence on band structure. However, SOC may also present more exotic effects, such as Rashba and Dresselhaus couplings. In this perspective, we start by recalling the main features of this effect and what makes HOP materials ideal candidates for the generation and tuning of spin-states. Then, we detail the main spectroscopy techniques able to characterize these effects and their application to HOP. Finally, we discuss potential applications in spintronics and in spin-orbitronics in those non-magnetic systems, that would complete the skill set of HOP and perpetuate its ride on the crest of the wave of popularity started with optoelectronics and photovoltaics. Graphical TOC EntryPage 2 of 29 2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d m a n u s c r i p tThe continuous success of halide hybrid organic-inorganic perovskites (HOP) as solar cell active materials follows several paths. The main activity after 2012 consisted in the search for improvement of the power conversion efficiency (PCE) in typical laboratory configuration (small area, controlled environment). It led to an unprecedented growth of the PCE that has repeatedly reached record values over 22%. 1,2 Meanwhile, another branch of HOP studies have been focused on improving the stability of those cells unfortunately sensitive to light and moisture. 3,4 Opting for various mixtures of halide and cations, 2 various forms, e.g. layered HOP, [5][6][7] or by encapsulating the materials, the stability went from few hours to several thousands hours. Encouraged by these breakthroughs, a third path has pushed the area of hight performance solar cells from less than 1 cm 2 up to 50 cm 2 with a PCE of 12.6%, 8 bringing the perovskite solar cells even closer to commercial use.A common point to all these record HOP materials is the presence of lead. Even though a large effort has been and still is dedicated to the search for efficient lead-free HOP materials, 9,10 their current record PCE remains around 6.4%. 11 It is certainly unfortunate for solar cells because of the known toxicity of lead, 12 even though solutions have early been proposed, 13,14 however, due to the large spin-orbit coupling (SOC) exhibited by Pb, it represents a great opportunity for optoelectronics, spintronics and spin-orbitronics applications where undesired heavy elements can find a place (e.g. arsenic, cadmium).The first identified effect of SOC in HOP materials has been a surprising giant splitting of conduction bands, 15,16 instead of the usual valence band splitting observed in classical semiconductors. 17 It has a strong influence on the band gap energy as well as on the effective masses and the oscillator strength of the optical transitions at the band gap. The chan...

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“…To increase the photocurrent and then the power conversion efficiency, light harvesting strategies have to be introduced in order to trap the light in the active region while minimizing reflection and parasitic absorption. Based on the significant prospective benefits of reduced thickness, such as lower production costs and feasibility of materials with lower carrier diffusion length, the design of efficient light-management concepts is achieving more and more importance [1][2][3][4]. Both more mature technologies and the emerging families of polymer and perovskite solar cells can gain from the implementation of such strategies [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Self-Organized Nanoscale Roughness Engineering for Broadband Light Trapping in Thin Film Solar Cells

et al. 2017

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Abstract:We present a self-organized method based on defocused ion beam sputtering for nanostructuring glass substrates which feature antireflective and light trapping effects. By irradiating the substrate, capped with a thin gold (Au) film, a self-organized Au nanowire stencil mask is firstly created. The morphology of the mask is then transferred to the glass surface by further irradiating the substrate, finally producing high aspect ratio, uniaxial ripple-like nanostructures whose morphological parameters can be tailored by varying the ion fluence. The effect of a Ti adhesion layer, interposed between glass and Au with the role of inhibiting nanowire dewetting, has also been investigated in order to achieve an improved morphological tunability of the templates. Morphological and optical characterization have been carried out, revealing remarkable light trapping performance for the largest ion fluences. The photon harvesting capability of the nanostructured glass has been tested for different preparation conditions by fabricating thin film amorphous Si solar cells. The comparison of devices grown on textured and flat substrates reveals a relative increase of the short circuit current up to 25%. However, a detrimental impact on the electrical performance is observed with the rougher morphologies endowed with steep v-shaped grooves. We finally demonstrate that post-growth ion beam restructuring of the glass template represents a viable approach toward improved electrical performance.

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Photovoltaic materials: Present efficiencies and future challenges

Cited by 1,772 publications

References 39 publications

Strongly Enhanced Photovoltaic Performance and Defect Physics of Air‐Stable Bismuth Oxyiodide (BiOI)

Strongly Enhanced Photovoltaic Performance and Defect Physics of Air‐Stable Bismuth Oxyiodide (BiOI)

Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Self-Organized Nanoscale Roughness Engineering for Broadband Light Trapping in Thin Film Solar Cells

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