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Colloidal quantum dot solar cells (CQD-SCs) are attractive in view of their wide optoelectronic tunability and manufacturing benefits. [1] The power conversion efficiency (PCE) of CQD-SCs has seen rapid advances over the past decade, reaching a PCE of 13.3% through improvements in CQD surface chemistry and device architecture. [2] To date, the most efficient CQD-SCs consist (Figure 1a) of a thin electron transport/hole-blocking layer of zinc oxide deposited on indium-tin-oxide; an active layer, comprising a CQD solid passivated using halide atoms; and a thin hole-transport layer (HTL) of CQDs cross-linked with 1,2-ethanedithiol (EDT). The EDTtreated CQD layer as the HTL provides well-optimized energy alignment and a desirable electric field distribution within the active layer. However, it also introduces drawbacks in view of its high density of trap states, [3] strong chemical interaction with the materials in the device stack, [4] and limited stability in encapsulated devices. [5] Importantly, it has a short diffusion length of tens of nm that precludes significant contribution to device photocurrent. [6] An ideal HTL in PbS CQD-SCs should combine appropriate energy levels to allow efficient hole-extraction and electronblocking; [7] sufficient hole mobility for efficient vertical charge transport; [8] a diffusion length enabling contribution to the device photocurrent; [9] materials processing that is compatible with underlying layers in the CQD device; [10] and excellent morphology and conformal coverage to prevent oxygen and moisture permeation. [11] Recently, p-type polymers such as TQ1, P3HT, PDTPBT, and PBDB-TF have been explored as an alternative HTL to replace the EDT-treated CQD layer, but these have failed to render high performance due to unfavorable energy level alignment. [12-15] Benzodithiophene (BDT)-based HTL (PTB7), an alternative to P3HT, has been introduced as a potential HTL in PbS CQD-SCs. The use of PTB7 led to increased PCE due to more suitable energy levels and relatively improved hole-mobility compared to P3HT. Yet, PTB7-based devices still exhibited a limited PCE of 9.6%, [8] significantly lower than of state-of-art CQDs-SC with a PCE of 13.3%, [2] due to low hole mobility of 10 −4 cm 2 V −1 s −1

The polymerization of diphenyldipropargylmethane was carried out with various transitionmetal catalysts. It was found that the M0CI5-and WCl6-based catalyst systems are very effective for the cyclopolymerization. The characterization of poly(diphenyldipropargylmethane) was carried out by IR, 'H NMR, 13C NMR, Raman, and UV-visible spectroscopies. The resulting polymer has a conjugated polyene backbone containing a six-membered cyclic structure. Poly(diphenyldipropargylmethane) was a dark violet solid of high molecular weight [Afn = (1-8) X 104], soluble in aromatic hydrocarbons, some ethers, and some ketones. The resulting polymer possesses excellent thermal and oxidative stability in air. In morphology studies of poly (diphenyldipropargylmethane), the fibrillar structure with a 200-300-A-diameter range was observed by scanning electron microscopy. The electrical conductivity and the magnetic properties of the resulting polymer upon doping were changed and these changes were studied by morphology, IR, UVvisible, and ESR spectra.

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