Organic position sensitive photodetectors based on lateral donor-acceptor concentration gradients

Cabanillas‐González, Juan; Peña‐Rodríguez, Ovidio; Lopez, Inma Suarez; Schmidt, Martín; Alonso, M. I.; Goñi, A. R.; Campoy‐Quiles, Mariano

doi:10.1063/1.3631731

Cited by 18 publications

(16 citation statements)

References 9 publications

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“…This device constitutes a proof of principle for a position sensitive photodetector as the response depends on the specific posi- tion in which light hits the device area. Compared to previous published organic PSDs, this device does not rely on the lateral resistivity of the ITO [11] or on the varying electric field distribution across the devices produced by a lateral gradual change in film thickness [15,16]. Instead, it is based on the produced gradient in morphology.…”

Section: Resultsmentioning

confidence: 99%

“…To avoid this, one could take advantage of the bathochromic shift produced by the different degree of crystallinity. By performing a ratiometric measurement at two different wavelengths [15] (for instance, at the position of the crystallization shoulder and the maximum of the EQE) a more linear dependence on position is obtained (Fig. 4 (b) bottom).…”

Section: Resultsmentioning

confidence: 99%

“…As only one pixel is needed, the organic PSD based on morphology gradients can achieve high resolution over large sizes without requiring complex electronics [14,16]. We have already shown in a previous publication how the spectral response of small molecule multilayer photodetectors can be spatially tuned by implementing wedge-shaped active layers [15]. In that case, the strong dependence of the indepth light distribution with film thickness was exploited for determining the position of the impinging light on the active area with a resolution better than 600 µm [16].…”

Section: Introductionmentioning

confidence: 99%

“…PSDs are a type of devices that allows detecting the specific place where light hits the surface of the detector [11][12][13][14][15][16]. PSDs have multiple applications from telecommunications (laser alignment) to robotics (following the movement of objects) passing through medical imaging.…”

Section: Introductionmentioning

confidence: 99%

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Continuous lateral gradients in film morphology for position sensitive detection and organic solar cell optimization

Campoy‐Quiles¹,

Randon²,

Mróz³

et al. 2013

Organic Photonics and Photovoltaics

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We present a method to fabricate binary organic donor and acceptor blends exhibiting a controlled lateral gradient in morphology. Upon combining photometry, ellipsometry and Xray maps together with photoinduced absorption measurements, we show how the gradual exposure to solvent vapor results in a varying degree of polymer crystallinity for the polythiophene/soluble fullerene system along one direction. These morphologically graded samples are characterized by a spectral photoresponse that depends on the specific location in the area of the device where the light beam impinges, a property that stands as proof-of-concept for position sensitive detection. Moreover, we demonstrate that the development of graded morphologies is an effective one-step method which allows for fast performance optimization of organic solar cells. Finally, the appropriateness of eight different solvents for morphology control via vapor annealing is evaluated in a time-effective way using the advanced method, which helps to identify boiling point and solubility as the key processing parameters.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Continuous lateral gradients in film morphology for position sensitive detection and organic solar cell optimization

Campoy‐Quiles¹,

Randon²,

Mróz³

et al. 2013

Organic Photonics and Photovoltaics

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“…Notice that considering that each film requires 60 µL of solution with a typical solid content of 20 mg mL −1 , only 1.2 mg of material is needed per film, and a single film already contains most of the required information regarding thickness effects of a specific blend. Interestingly, this method can be used for other applications beyond OPV optimization, including the study of the geometrical confinement on phase transition temperatures, [32] determination of exciton diffusion lengths, [33] fabrication of position sensitive photodetectors, [34] or as miniature spectrophotometers based on microcavity resonators with a wedged active layer. [35] We extend here this method beyond thickness gradients to also include the preparation of films with D:A composition gradients.…”

Section: Casting Methodologymentioning

confidence: 99%

High‐Throughput Multiparametric Screening of Solution Processed Bulk Heterojunction Solar Cells

Sánchez-Díaz

Rodríguez‐Martínez

Córcoles-Guija

et al. 2018

Adv Elect Materials

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(MDMO-PPV) or poly(3-hexylthiophene) (P3HT) combined with soluble fullerenes, [6,7] up to current PCE values exceeding 10% for several systems. [9][10][11][12][13] There is no specific fundamental limitation to organic materials that indicates that much higher values are not possible, and the number of potential candidates is nearly infinite. Indeed, the organic nature of the photoactive materials offers a myriad of possibilities to modify their chemical structure; for the case of conjugated polymers, there exists a vast assortment of combinations depending on the choice of moieties, the bridging atoms, the length and branching points of the alkyl side chains, and the molecular weight, to name but a few. Using search engines to inspect the literature, we estimate that in the last ten years ≈5000 organic conjugated materials have been tested in BHJ solar cells, albeit only a few tenths have been studied and optimized in depth. While applied quantum theory can help to select promising candidates, [14][15][16] the final performance often depends on a number of issues difficult to predict a priori, such as solubility, miscibility of compounds, tendency to crystallize, exact energy levels in the blend, etc. In practice, this means that for a given promising backbone, a family of systems need to be tested, including different side chains, molecular weights, donor:acceptor combinations, etc. [17] Within this large and uncharted spectrum of materials and processing variables, combinatorial screening methodologies are highly on demand to speed up their exploration while helping the technology to approach the theoretical Shockley-Queisser limit of >20% PCE. [18,19] From the engineering point of view, three main aspects must be addressed for the evaluation of a material system for BHJ solar cells, namely the active layer thickness, the donor-acceptor (D:A) blending ratio and the nanoscale morphology (typically controlled by deposition conditions, thermal annealing, and use of additives). Ideally, those three variables can be optimized separately and to some extent it is usually an acceptable approximation; however, the full potential of a novel active layer material requires for fine tuning of the preparation conditions that take into consideration the subtle interplay between them. [20] For instance, the optimum thickness is often found close to the first interference maximum, which is governed by the refractive index of the active layer; this, on the other hand, will be a function of the D:A ratio (fullerenes typically have higher refractive index than polymers) and the degree of crystallinity One of the major bottlenecks in the development of organic photovoltaics is the time needed to evaluate each material system. This time ranges from weeks to months if different variables such as blend composition, thickness, annealing, and additives are to be explored. In this study, the use of lateral gradients is proposed in order to evaluate the photovoltaic potential of a material system up to 50 times faster. A platform that c...

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Organic Light Detectors: Photodiodes and Phototransistors

et al. 2013

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While organic electronics is mostly dominated by light-emitting diodes, photovoltaic cells and transistors, optoelectronics properties peculiar to organic semiconductors make them interesting candidates for the development of innovative and disruptive applications also in the field of light signal detection. In fact, organic-based photoactive media combine effective light absorption in the region of the spectrum from ultraviolet to near-infrared with good photogeneration yield and low-temperature processability over large areas and on virtually every substrate, which might enable innovative optoelectronic systems to be targeted for instance in the field of imaging, optical communications or biomedical sensing. In this review, after a brief resume of photogeneration basics and of devices operation mechanisms, we offer a broad overview of recent progress in the field, focusing on photodiodes and phototransistors. As to the former device category, very interesting values for figures of merit such as photoconversion efficiency, speed and minimum detectable signal level have been attained, and even though the simultaneous optimization of all these relevant parameters is demonstrated in a limited number of papers, real applications are within reach for this technology, as it is testified by the increasing number of realizations going beyond the single-device level and tackling more complex optoelectronic systems. As to phototransistors, a more recent subject of study in the framework of organic electronics, despite a broad distribution in the reported performances, best photoresponsivities outperform amorphous silicon-based devices. This suggests that organic phototransistors have a large potential to be used in a variety of optoelectronic peculiar applications, such as a photo-sensor, opto-isolator, image sensor, optically controlled phase shifter, and opto-electronic switch and memory.

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Organic position sensitive photodetectors based on lateral donor-acceptor concentration gradients

Cited by 18 publications

References 9 publications

Continuous lateral gradients in film morphology for position sensitive detection and organic solar cell optimization

Continuous lateral gradients in film morphology for position sensitive detection and organic solar cell optimization

High‐Throughput Multiparametric Screening of Solution Processed Bulk Heterojunction Solar Cells

Organic Light Detectors: Photodiodes and Phototransistors

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