The energy costs associated with separating tightly bound excitons (photoinduced electron-hole pairs) and extracting free charges from highly disordered low-mobility networks represent fundamental losses for many low-cost photovoltaic technologies. We report a low-cost, solution-processable solar cell, based on a highly crystalline perovskite absorber with intense visible to near-infrared absorptivity, that has a power conversion efficiency of 10.9% in a single-junction device under simulated full sunlight. This "meso-superstructured solar cell" exhibits exceptionally few fundamental energy losses; it can generate open-circuit photovoltages of more than 1.1 volts, despite the relatively narrow absorber band gap of 1.55 electron volts. The functionality arises from the use of mesoporous alumina as an inert scaffold that structures the absorber and forces electrons to reside in and be transported through the perovskite.

https://science.sciencemag.org/content/sci/early/2012/10/03/science.1228604.full.pdf

Efficient Hybrid Solar Cells Based on Meso-Superstructured Organometal Halide Perovskites

Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

/pdf/dye-sensitized-solar-cells-50b0w2bhsr.pdf

Dye-Sensitized Solar Cells

Many different photovoltaic technologies are being developed for large-scale solar energy conversion. The wafer-based first-generation photovoltaic devices have been followed by thin-film solid semiconductor absorber layers sandwiched between two charge-selective contacts and nanostructured (or mesostructured) solar cells that rely on a distributed heterojunction to generate charge and to transport positive and negative charges in spatially separated phases. Although many materials have been used in nanostructured devices, the goal of attaining high-efficiency thin-film solar cells in such a way has yet to be achieved. Organometal halide perovskites have recently emerged as a promising material for high-efficiency nanostructured devices. Here we show that nanostructuring is not necessary to achieve high efficiencies with this material: a simple planar heterojunction solar cell incorporating vapour-deposited perovskite as the absorbing layer can have solar-to-electrical power conversion efficiencies of over 15 per cent (as measured under simulated full sunlight). This demonstrates that perovskite absorbers can function at the highest efficiencies in simplified device architectures, without the need for complex nanostructures.

Efficient planar heterojunction perovskite solar cells by vapour deposition

Within the space of a few years, hybrid organic–inorganic perovskite solar cells have emerged as one of the most exciting material platforms in the photovoltaic sector. This review describes the rapid progress that has been made in this area.

The emergence of perovskite solar cells

Organic electronics are beginning to make significant inroads into the commercial world, and if the field continues to progress at its current, rapid pace, electronics based on organic thin-film materials will soon become a mainstay of our technological existence. Already products based on active thin-film organic devices are in the market place, most notably the displays of several mobile electronic appliances. Yet the future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.

The path to ubiquitous and low-cost organic electronic appliances on plastic

Intrinsic time-of-flight hole mobilities (${\ensuremath{\mu}}^{+}$) were obtained in naphthalene single crystals down to 4.2 K. Between 300 and 150 K the tensor component ${\ensuremath{\mu}}_{\mathrm{aa}}^{+}$ increases with decreasing temperature T, obeying a \ensuremath{\mu}\ensuremath{\propto}${T}^{n}$ dependence, with n=-2.9. At low temperature the hole transport becomes nonlinear (sub-Ohmic) with the hole velocity tending to saturate with increasing electric field, E, at about 2\ifmmode\times\else\texttimes\fi{}${10}^{6}$ cm/s. The highest experimental ${\ensuremath{\mu}}_{\mathrm{aa}}^{+}$ (obtained at the lowest E which allowed the observation of a distinct hole transit pulse) was 400 ${\mathrm{cm}}^{2}$/V s at 10 K and 3 kV/cm. It will be shown that the low-temperature results can be understood in terms of a standard band-model description, whereas the continuation of the experimental temperature-dependence law (\ensuremath{\mu}\ensuremath{\propto}${T}^{n}$) (for both holes and electrons) into the high-temperature regime remains a problem for future theoretical work. Electron transits were obtained down to 22.5 K [${\ensuremath{\mu}}_{\mathrm{aa}}^{\mathrm{\ensuremath{-}}}$ (22.5 K) = 24.5 ${\mathrm{cm}}^{2}$/V s]. No field dependence of the electron mobility was detected.

Hot holes in naphthalene: High, electric-field-dependent mobilities

The field-effect passivation of the interface of thermal oxides on silicon is experimentally investigated by depositing corona charges on the oxide of solar cells and of lifetime test structures. The open circuit voltage of solar cells with interdigitated rear contacts can be increased by +12 mV or decreased by −34 mV, respectively, by depositing positive or negative corona charges on top of the front oxide. The resulting effective surface recombination velocity, Seff, is determined on carrier lifetime test structures for different injection levels and charge densities using microwave-detected photoconductance decay and a new expression for the Auger-limited bulk lifetime. Seff can be varied between 24 cm/s and 538 cm/s on a 1 Ω cm p-type wafer with a thermal oxide of 105 nm thickness. The measurements are compared with theoretical predictions of an analytical model for the calculation of the surface recombination. Measured values for the capture cross sections and interface trap densities are used for th...

Field-effect passivation of the SiO2Si interface

https://onlinelibrary.wiley.com/doi/pdf/10.1002/pip.974

Solar cell efficiency tables (version 35)

Physical and Technical Basics.- Experimental Technique.- Theory.- Measurement Strategies.- Typical Applications.- Summary and Outlook.

Lock-in Thermography: Basics and Use for Evaluating Electronic Devices and Materials

Procedures for measuring the spectral response of multi-junction cells in general require variation of the bias spectrum and voltage biasing. It is shown that a refined procedure including optimization of bias spectrum and voltage is necessary to minimize a measurement artifact, which appears if the subcell under test has non-ideal properties, such as a low shunt resistance or a low reverse breakdown voltage.

This measurement artifact is often observed on measuring the spectral response of the Ge bottom cell of GaInP/Ga(In)As/Ge triple-junction cells. The main aspect of the measurement artifact is that the response of another subcell is simultaneously measured, while at the same time the signal of the Ge subcell is too low. Additionally, the shape of the spectral response curve is influenced under certain measurement conditions. In this paper the measurement artifact is thoroughly discussed by measurement results and simulation. Based on this analysis, a detailed procedure for the spectral response measurement of multi-junction cells is developed, specially designed to minimize such measurement artifacts. Copyright © 2003 John Wiley & Sons, Ltd.

Wilhelm Warta

Papers

Hot holes in naphthalene: High, electric-field-dependent mobilities

Field-effect passivation of the SiO2Si interface

Solar cell efficiency tables (version 35)

Lock-in Thermography: Basics and Use for Evaluating Electronic Devices and Materials

Spectral response measurements of monolithic GaInP/Ga(In)As/Ge triple-junction solar cells : measurement artifacts and their explanation