5 research outputs found

    Efficient All-Printable Solid-State Dye-Sensitized Solar Cell Based on a Low-Resistivity Carbon Composite Counter Electrode and Highly Doped Hole Transport Material

    No full text
    Monolithic device architectures provide a route to large-area mesoporous solar cell manufacture through scalable solution-processed fabrication. A limiting factor in device scale-up is availability of low-resistivity printable counter electrode materials and reliable doped charge transport materials. We report an efficient all-printable monolithic solid-state dye-sensitized solar cell (ss-DSC) based on a high-conductivity porous carbon counter electrode and a highly doped 2,2′,7,7′-tetrakis­(<i>N</i>,<i>N</i>-di-4-methoxy­phenyl­amino)-9,9′-spiro­bi­fluorene (spiro-OMeTAD) hole transport material (HTM). A review of current state-of-the-art printable porous counter electrodes in DSC literature was conducted and identified blends of graphite/carbon black as promising composites for high-conductivity electrodes. Direct ex situ oxidation of spiro-OMeTAD produced a stable HTM dopant, and its incorporation with one of the lowest-resistivity graphite/carbon black composite materials reported to date drastically decreases device series resistance, particularly that of the porous insulating spacer. Doping improved all performance parameters, and following optimization we demonstrate scaled-up 1.21 cm<sup>2</sup> (1.01 cm<sup>2</sup> masked) devices achieving a maximum efficiency of 3.34% (average, 3.05 ± 0.23%)

    Tunable Crystallization and Nucleation of Planar CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> through Solvent-Modified Interdiffusion

    No full text
    A smooth and compact light absorption perovskite layer is a highly desirable prerequisite for efficient planar perovskite solar cells. However, the rapid reaction between CH<sub>3</sub>NH<sub>3</sub>I methylammonium iodide (MAI) and PbI<sub>2</sub> often leads to an inconsistent CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> crystal nucleation and growth rate along the film depth during the two-step sequential deposition process. Herein, a facile solvent additive strategy is reported to retard the crystallization kinetics of perovskite formation and accelerate the MAI diffusion across the PbI<sub>2</sub> layer. It was found that the ultrasmooth perovskite thin film with narrow crystallite size variation can be achieved by introducing favorable solvent additives into the MAI solution. The effects of dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, chlorobenzene, and diethyl ether additives on the morphological properties and cross-sectional crystallite size distribution were investigated using atomic force microscopy, X-ray diffraction, and scanning electron microscopy. Furthermore, the light absorption and band structure of the as-prepared CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> films were investigated and correlated with the photovoltaic performance of the equivalent solar cell devices. Details of perovskite nucleation and crystal growth processes are presented, which opens new avenues for the fabrication of more efficient planar solar cell devices with these ultrasmooth perovskite layers

    The Influence of the Work Function of Hybrid Carbon Electrodes on Printable Mesoscopic Perovskite Solar Cells

    No full text
    In printable mesoscopic perovskite solar cells (PSCs), carbon electrodes play a significant role in charge extraction and transport, influencing the overall device performance. The work function and electrical conductivity of the carbon electrodes mainly affect the open-circuit voltage (<i>V</i><sub>OC</sub>) and series resistance (<i>R</i><sub>s</sub>) of the device. In this paper, we propose a hybrid carbon electrode based on a high-temperature mesoporous carbon (m-C) layer and a low-temperature highly conductive carbon (c-C) layer. The m-C layer has a high work function and large surface area and is mainly responsible for charge extraction. The c-C layer has a high conductivity and is responsible for charge transport. The work function of the m-C layer was tuned by adding different amounts of NiO, and at the same time, the conductivities of the hybrid carbon electrodes were maintained by the c-C layer. It was supposed that the increase of the work function of the carbon electrode can enhance the <i>V</i><sub>OC</sub> of printable mesoscopic PSCs. Here, we found the <i>V</i><sub>OC</sub> of the device based on hybrid carbon electrodes can be enhanced remarkably when the insulating layer has a relatively small thickness (500–1000 nm). An optimal improvement in <i>V</i><sub>OC</sub> of up to 90 mV could be achieved when the work function of the m-C was increased from 4.94 to 5.04 eV. When the thickness of the insulating layer was increased to ∼3000 nm, the variation of <i>V</i><sub>OC</sub> as the work function of m-C increased became less distinct
    corecore