Controlled Defects of Fluorine-incorporated ZnO Nanorods for Photovoltaic Enhancement

Abstract

Anion passivation effect on metal-oxide nano-architecture offers a highly controllable platform for improving charge selectivity and extraction, with direct relevance to their implementation in hybrid solar cells. In current work, we demonstrated the incorporation of fluorine (F) as an anion dopant to address the defect-rich nature of ZnO nanorods (ZNR) and improve the feasibility of its role as electron acceptor. The detailed morphology evolution and defect engineering on ZNR were studied as a function of F-doping concentration (x). Specifically, the rod-shaped arrays of ZnO were transformed into taper-shaped arrays at high x. A hypsochromic shift was observed in optical energy band gap due to the Burstein-Moss effect. A substantial suppression on intrinsic defects in ZnO lattice directly epitomized the novel role of fluorine as an oxygen defect quencher. The results show that 10-FZNR/P3HT device exhibited two-fold higher power conversion efficiency than the pristine ZNR/P3HT device, primarily due to the reduced Schottky defects and charge transfer barrier. Essentially, the reported findings yielded insights on the functions of fluorine on (i) surface –OH passivation, (ii) oxygen vacancies (Vo) occupation and (iii) lattice oxygen substitution, thereby enhancing the photo-physical processes, carrier mobility and concentration of FZNR based device.

Influence of ZnO Surface Modification on the Photocatalytic Performance of ZnO/NiO Thin Films

“…As expected, the XPS survey spectra of Z1, Z2 and their corresponding heterostructures ( Figure S2 in Supplementary Information) showed the presence of Zn, Ni and O, but also of carbon and hydroxyl species adsorbed on the surface of the Z1 sample [26,48,55]. The detailed XPS spectra of Zn2p, Ni2p, O1 s lines and valence band for all the samples are shown in Fig.…”

“…The shoulder in the O1s line (Fig. 5b, f) at the binding energy (BE) of 532 eV is attributed to -OH adsorbates [48,56]. A slight shift of the Zn2p BE of about 0.48 eV ( Fig.…”

“…Also, the concentration of deep level defects was slightly reduced since part of the oxygen vacancies were passivated through surface cleaning [46,47]. In addition, the blue shift of DLE peak after thermal treatment (from 602 nm for Z1 to 584 nm for Z2) suggests that part of the V O were ionized through surface cleaning [43,[48][49][50][51].…”

Gap Plasmon of Virus‐Templated Biohybrid Nanostructures Uplifting the Performance of Organic Optoelectronic Devices

“…Indirectly, the NP‐M13 interlayer helped to improve the ohmic contact between ZnO and polymer, thus enabling more efficient charge transport across the ZnO/polymer interface. [ 36,37 ] A series of device characterizations were conducted to investigate the charge transport dynamics of the OSCs, including photoluminescence (PL) (Figure S11, Supporting Information), transient photovoltage (Figure S12, Supporting Information), transient photocurrent (Figure S13, Supporting Information), charge extraction by linearly increasing voltage (Figure S14 and Table S3, Supporting Information), and impedance measurements (Figure S15, Supporting Information). [ 38,39 ] The characterization results coherently confirm that there was more efficient charge extraction and lesser bimolecular charge recombination (Figure S16, Supporting Information) in the Ag/AuNP‐M13 incorporated devices than the pristine device.…”

Improved Stability of Polymer Solar Cells in Ambient Air via Atomic Layer Deposition of Ultrathin Dielectric Layers

“…This has the net result of reducing the energy offset between the LUMO of P3HT and the conduction band of ALD-modified ZnO promoting fast, energetically downhill, electron transfer from P3HT to ALD dielectric-coated ZnO, therefore, reducing the exciton lifetime. [34,72] Identically, the simultaneous suppression of defect-induced hole trapping and enhancement of electron transfer in ALD-coated ZnO granted minor deviations in exciton lifetimes of 40 nm thick PTB7 films deposited on ZnO substrates; this was estimated from TRPL measurements for excitation at 468 nm and detection at 790 nm (Figure 6c; Table S3, Supporting Information) and 830 nm (Figure 6d; Table S4, Supporting information). In particular, the estimated exciton lifetimes of PTB7 deposited Figure S15, Supporting Information) verified that charge separation occurring at the ZnO/Al 2 O 3 /P3HT interfaces represents a phenomenon predominantly governed by the suppression of the intrinsic deep defects in ZnO.…”