Sequential layers of the high‐k dielectric ZrO2 and the electron transporting semiconductors ZnO and Li‐doped ZnO are deposited onto conductive indium tin oxide electrodes using spray pyrolysis. With ...these structures, thin‐film transistors are fabricated with operating voltages below 6 V and maximum electron mobilities on the order of 85 cm2 V−1 s−1.
The use of a simple deposition technique, namely spray pyrolysis, for the fabrication of high‐mobility, low‐voltage ZnO transistors and simple integrated circuits is demonstrated. The method is ...compatible with large‐area deposition and could potentially address both the issue of manufacturing cost and high operating voltages.
Interlayer lithography is used to pattern highly conductive, solution‐processed, reduced graphene oxide source and drain electrodes down to 10 μm gaps. These patterned electrodes allow for the ...fabrication of high‐performance organic thin‐film transistors and complementary circuits. The method offers a viable route towards organic electronics fabricated entirely by solution processing.
The effect of replacing 6,6‐phenyl‐C₆₁ butyric acid methyl ester (PCBM) by its multiadduct analogs (bis‐PCBM and tris‐PCBM) in bulk heterojunction organic solar cells with ...poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) is studied in terms of blend film microstructure, photophysics, electron transport properties, and device performance. Although the power conversion efficiency of the blend with bis‐PCBM is similar to the blend with PCBM, the performance of the devices with tris‐PCBM is considerably lower as a result of small photocurrent. Despite the lower electron affinity of the fullerene multiadducts, μs‐ms transient absorption measurements show that the charge generation efficiency is similar for all three fullerenes. The annealed blend films with multiadducts show a lower degree of fullerene aggregation and lower P3HT crystallinity than the annealed blend films with PCBM. We conclude that the reduction in performance is due largely to poorer electron transport in the blend films from higher adducts, due to the poorer fullerene network formation as well as the slower electron transport within the fullerene phase, confirmed here by field effect transistor measurements.
The electrical stability of low-voltage organic transistors based on phosphonic acid self-assembled monolayer (SAM) dielectrics is investigated using four different semiconductors. The threshold ...voltage shift in these devices shows a stretched-exponential time dependence under continuous gate bias with a relaxation time in the range of 10(3)-10(5) s, at room temperature. Differences in the bias instability of transistors based on different self-assembled monolayers and organic semiconductors suggest that charge trapping into localized states in the semiconductor is not the only mechanism responsible for the observed instability. By applying 1-5 s long programming voltage pulses of 2-3 V in amplitude, a large reversible threshold voltage shift can be produced. The retention time of the programmed state was measured to be on the order of 30 h. The combination of low voltage operation and relatively long retention times makes these devices interesting for ultra-low power memory applications.
Solution‐based semiconductors give rise to the next generation of thin‐film electronics. Solution‐based silicon as a starting material is of particular interest because of its favorable properties, ...which are already vastly used in conventional electronics. Here, the application of a silicon precursor based on neopentasilane for the preparation of thin‐film solar cells is reported for the first time, and, for the first time, a performance similar to conventional fabrication methods is demonstrated. Because three different functional layers, n‐type contact layer, intrinsic absorber, and p‐type contact layer, have to be stacked on top of each other, such a device is a very demanding benchmark test of performance of solution‐based semiconductors. Complete amorphous silicon n‐i‐p solar cells with an efficiency of 3.5% are demonstrated, which significantly exceeds previously reported values.
Solution‐based semiconductors are a promising new material class in thin‐film electronics. So far, the quality of the device made of such material has been rather poor. Here, solar cells made of solution‐based silicon with an efficiency of 3.5%, exceeding previous results by a factor of seven, are reported. This may pave the way for development of industrial applications.
We report on n-channel organic field-effect transistors (OFETs) based on the solution processable methanofullerenes 6,6-phenyl-C
61-butyric acid ester (60PCBM) and 6,6-phenyl-C
71-butyric acid methyl ...ester (70PCBM). Despite the fact that both derivatives form glassy films when processed from solution, their electron mobilities are high and on the order of 0.21
cm
2/V
s and 0.1
cm
2/V
s, for 60PCBM and 70PCBM, respectively. Although the derived mobility of 60PCBM is comparable to the best values reported in the literature, the electron mobility of 70PCBM is the highest value reported to date for any C
70 based molecule. We note that this is the only report in which C
60 and C
70 methanofullerenes exhibit comparable electron mobilities. The present findings could have significant implications in the area of large-area organic electronics and organic photovoltaics where C
60 derivatives have so far been the most widely used electron acceptor materials.
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