Search Results

You searched for all publications:

with publication states 'Published (Approved)'

Search Again...

These results only include publications that have been reviewed and processed by Diamond Light Source. To also view papers that have not yet been processed click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

Exact matches
Related results

3 items found (0 items not approved), displaying all items.1

Instruments / Technical Area	Publication Details	Published
I22-Small angle scattering & Diffraction	Novel materials and deposition techniques for solution processed solar cells Alexander Thomas Barrows Open Access Show Abstract ▼ Abstract: Whilst many advances have been made in the field of solution processed solar cells (SPSCs), there is still much work to be done if they are to fulfil their potential and reduce the cost of commercial photovoltaic devices. This thesis aims to assist in moving towards this objective by investigating ways to overcome some of the barriers to the commercialization of SPSCs. Such barriers include the costly and mechanically brittle electrode material of indium tin oxide, the use of solution deposition techniques which are not compatible with large-scale production, and a lack of understanding of the properties of promising new semiconducting materials such as organometal halide perovskites. In this work a novel indium-free multilayer semi-transparent electrode has been fabricated and incorporated as the anode in polymer solar cells. Whilst molybdenum oxide is typically used as the ‘seed layer’ material in such trilayer structures, its replacement with tellurium dioxide has been found to lead to an enhanced transmittance in the optimised electrodes and to an increased short circuit current when such electrodes are employed in polymer solar cells. The roll-to-roll compatible deposition technique of ultrasonic spray-coating has, for the first time, been successfully used for the fabrication of films of the organometal trihalide perovskite CH3NH3PbI3-xClx. Such films were subsequently successfully employed as the active layer in planar solar cells. This deposition technique is then extended to hole transporting and electron transporting materials in order to move towards a fully spray-deposited solar cell. Finally, a combination of structural investigation techniques have been employed to monitor the formation of the perovskite CH3NH3PbI3-xClx during thermal annealing of a precursor film. In-situ X-ray scattering measurements are used together with ex-situ scanning electron microscopy in order to correlate the evolution of the film during annealing to solar cell performance. In addition, the activation energy for the transition from precursor to perovskite has been calculated.	Dec 2015
I22-Small angle scattering & Diffraction	Monitoring the formation of a CH3NH3PbI3–xClx perovskite during thermal annealing using X-ray scattering Alex Barrows , Samuele Lilliu , Andrew Pearson , David Babonneau , Alan Dunbar , David Lidzey Advanced Functional Materials DOI: 10.1002/adfm.201601309 Open Access Show Abstract ▼ Abstract: Grazing incidence wide and small angle X-ray scattering (GIWAXS and GISAXS) measurements have been used to study the crystallization kinetics of the organolead halide perovskite CH3NH3PbI3–xClx during thermal annealing. In situ GIWAXS measurements recorded during annealing are used to characterize and quantify the transition from a crystalline precursor to the perovskite structure. In situ GISAXS measurements indicate an evolution of crystallite sizes during annealing, with the number of crystallites having sizes between 30 and 400 nm increasing through the annealing process. Using ex situ scanning electron microscopy, this evolution in length scales is confirmed and a concurrent increase in film surface coverage is observed, a parameter crucial for efficient solar cell performance. A series of photovoltaic devices are then fabricated in which perovskite films have been annealed for different times, and variations in device performance are explained on the basis of X-ray scattering measurements.	May 2016
I07-Surface & interface diffraction	An X-ray scattering and electron microscopy study of methylammonium bismuth perovskites for solar cell applications Chan Kyu Kwak , Alex T. Barrows , Andrew J. Pearson , David G. Lidzey , Alan D. F. Dunbar Journal Of Materials Research 32, 1888 - 1898 DOI: 10.1557/jmr.2016.499 Diamond Proposal Number(s): [11676] Show Abstract ▼ Abstract: Photovoltaics made from organic-inorganic hybrid perovskite semiconductors are attracting significant interest due to their ability to harvest sunlight with remarkable efficiency. The presence of lead in the best performing devices raises concerns regarding their toxicity, a problem that may create barriers to commercialization. Hybrid perovskites with reduced lead content are being investigated to overcome this issue and here we evaluate bismuth as a possible lead substitute. For a series of hybrid perovskite films with the general composition CH3NH3(Pb yBi1-y)I3-xCl x, we characterize their optical and structural properties using UV-Vis spectroscopy, scanning electron microscopy and grazing incidence wide angle X-ray scattering. We show that they form crystalline structures with an optical band gap, around 2 eV for CH3NH3BiI3. However, preliminary solar cell tests show low power conversion efficiencies (<0.01%) due to both incomplete precursor conversion and material de-wetting from the substrate. The overall outcome is severely limited photocurrent. With current processing methods the general applicability of hybrid bismuth perovskites in photovoltaics may be limited.	May 2017

Publications Database

Search Results

You searched for all publications:

Search Again...

Subject Areas (check all that apply) select all

Instruments used to collect data (check all that apply) select all

Collaborations involved (check all that apply) select all

Diamond Offline Facilities used

Relevant Technical Areas (check all that apply) select all

Menu for Anonymous User