You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Active Layer-Incorporated, Spectrally-Tuned Au/SiO2 Core/Shell Nanorod-Based Light Trapping for Organic Photovoltaics. We demonstrated that incorporation of octadecyltrimethoxysilane (OTMS) functionalized, spectrally tuned, gold/silica (Au/SiO2) core/shell nanospheres and nanorods into the active layer of an organic photovoltaic (OPV) device led to an in increase photo conversion efficiency (PCE). A silica shell layer was added onto Au core nanospheres and nanorods in order to provide an electrically insulating surface that does not interfere with carrier generation and transport inside the active layer. Functionalization of the Au/SiO2 core/shell nanoparticles with the OTMS organic ligand was then necessary in order to transfer the Au/SiO2 core/shell nanoparticles from an ethanol solution into an OPV polymer-compatible solvent, such as dichlorobenzene (DCB). The OTMS-functionalized Au/SiO2 core/shell nanorods and nanospheres were then incorporated into the active layers of two OPV polymer systems: a poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCB60M) OPV device and a poly[2,6-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,4-b]dithiophene-alt-5-dibutyloctyl-3,6-bis(5-bromothiophen-2-yl) pyrrolo[3,4-c]pyrrole-1,4-dione] (PBDTT-DPP:PC60BM) OPV device. For the P3HT:PC60BM polymer with a band edge of ~700 nm, the addition of the core/shell nanorods with an aspect ratio (AR) of ~2.5 (extinction peak ~670 nm) resulted in a 7.1% improvement in PCE, while for the PBDTT-DPP:PC60BM polymer with a band edge ~860 nm, the addition of core/shell nanorods with an AR of ~4 (extinction peak ~830 nm) resulted in a 14.4% improvement in PCE. The addition of Au/SiO2 core/shell nanospheres to the P3HT:PC60BM-polymer resulted in a 2.7% improvement in PCE, while their addition to a PBDTT-DPP:PC60BM polymer resulted in a 9.1% improvement. The PCE and Jsc enhancements were consistent with external quantum efficiency (EQE) measurements and the EQE enhancements spectrally matched the extinction spectra of Au/SiO2 nanospheres and nanorods in both OPV polymer systems.
{"Chemical": ["SiO2", "dichlorobenzene", "[6,6]-phenyl-C61-butyric acid methyl ester", "DCB", "Au", "PCB60M", "P3HT", "ethanol", "OTMS", "PBDTT-DPP", "silica", "PC60BM", "octadecyltrimethoxysilane", "poly(3-hexylthiophene)", "poly[2,6-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,4-b]dithiophene-alt-5-dibutyloctyl-3,6-bis(5-bromothiophen-2-yl) pyrrolo[3,4-c]pyrrole-1,4-dione]"]}