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Dr Andrei Sapelkin

Lecturer

Department School of Physics and Astronomy
 G O Jones 126, Mile End
Telephone +44 (0)20 7882 3414
Email a.sapelkin@qmul.ac.uk
Homepage http://ph.qmul.ac.uk/directory/a.sapelkin

Research Keywords

X-ray absorption spectroscopy, Nanomaterials, Carbon nanotubes, quantum electronics

Research Interests

Andrei V. Sapelkin has research interests in semiconductor quantum dots (SQDs) preparation, characterisation and their use in bio-applications. Specifically, he has been looking into effects of various synthesis routes on light emission in nanostructures. Semiconductor nano-crystals have captivated the imagination of scientists and engineers since their technological potential became evident over two decades ago. This is especially true for semiconductor quantum dots, where quantum size effects and carrier confinement allow unprecedented control over optical and electronic properties. Leading the way in this field, in both theoretical understanding and demonstrated applications, is indisputably the cadmium-based II-VI quantum dots discovered by Brus in 1980s. However, concerns regarding their toxicity are yet to be resolved calling for the advancement of alternative nontoxic materials, including the group IV (Si, Ge) semiconductor nano-crystals. Our interest is in bio-application of quantum dots and to this end we adopted synthesis routes that yield Ge QDs in form of suspension (by etching and now by colloidal synthesis, Fig. 1). These nano-particles show low toxicity and photoluminescence in a visible range (500-700 nm) and hence could potentially be suitable for bio-application. Our synthesis methods provide a degree of control over surface termination and also over the light emission properties.

We work together with Dr. A. Wheeler, Blizard Institute, QMUL to assess the possibility of using Ge QDs for super-resolution imaging of live cells. This work requires a combination of in-house characterisation techniques (e.g.. Raman, Photoluminescence, Fluorescence Imaging) and structural methods (e.g. XAS) available at the large scale facilities such as Diamond Light Source. Furthermore, understanding of relationship between atomic, electronic structure and optical properties requires firm theoretical support and we work together with Dr. K. Trachenko, SPA, QMUL.

Another long standing interest is effects of high hydrostatic pressure on structural and optical properties of novel materials such as topologically disordered solids and nanostructures. This led to his interest in the development of experimental techniques for local structural characterisation of materials under pressure using synchrotron radiation. He investigated in details behavior of diamond spikes in EXAFS spectra collected under pressure in DACs, demonstrating the possibility of data collection in much wider range of energies than thought was possible before. He was involved in initiation and preparation of the case for I20-X-ray spectroscopy (XAS-3) beamline at new UK synchrotron radiation source - Diamond. He then served as a member of the working group for XAS3. The beamline is now approved for funding and will be operational by 2009.

Key Publications

Zhang Y, Ersoy O, Karatutlu A, Little W and Sapelkin A (2016). Local structure of Ge quantum dots determined by combined numerical analysis of EXAFS and XANES data. J Synchrotron Radiat  vol. 23, (1) 253-259. 10.1107/S160057751501913X

Karatutlu A, Little W, Ersoy O, Zhang Y, Seker I and Sapelkin A (2015). Laser-induced particle size tuning and structural transformations in germanium nanoparticles prepared by stain etching and colloidal synthesis route. Journal of Applied Physics  vol. 118, (24) 10.1063/1.4939066

Corsini NRC, Zhang Y, Little WR, Karatutlu A, Ersoy O, Haynes PD, Molteni C, Hine NDM, Hernandez I, Gonzalez J, Rodriguez F, Brazhkin VV and Sapelkin A (2015). Pressure-Induced Amorphization and a New High Density Amorphous Metallic Phase in Matrix-Free Ge Nanoparticles. Nano Lett  vol. 15, (11) 7334-7340. 10.1021/acs.nanolett.5b02627

Karatutlu A, Song M, Wheeler AP, Ersoy O, Little WR, Zhang Y, Puech P, Boi FS, Luklinska Z and Sapelkin AV (2015). Synthesis and structure of free-standing germanium quantum dots and their application in live cell imaging. Royal Society of Chemistry  Rsc Advances  vol. 5, (26) 20566-20573. 10.1039/c5ra01529d

Ye HQ, Li Z, Peng Y, Wang CC, Li TY, Zheng YX, Sapelkin A, Adamopoulos G, Hernandez I, Wyatt PB and Gillin WP (2014). Organo-erbium systems for optical amplification at telecommunications wavelengths. Nature Publishing Group  Nature Materials  vol. 13, (April 2014) 382-386. 10.1038/NMAT3910

2017

SUKHORUKOV G, Goryacheva I and Sapelkin A (2017). Carbon nanodots: mechanisms of photoluminescence and principles of applicationReview. Elsevier  Trends in Analytical Chemistry  10.1016/j.trac.2017.02.012

Song M, Karatutlu A, Ali I, Ersoy O, Zhou Y, Yang Y, Zhang Y, Little WR, Wheeler AP and Sapelkin AV (2017). Spectroscopic super-resolution fluorescence cell imaging using ultra-small Ge quantum dots. Opt Express  vol. 25, (4) 4240-4253. 10.1364/OE.25.004240

2016

Zhang Y, Ersoy O, Karatutlu A and Sapelkin A (2016). Local structure of amorphous and nanoscale systems by numerical XANES calculations. Journal of Non-Crystalline Solids  vol. 451, 10-15. 10.1016/j.jnoncrysol.2016.07.001

Gao H, Sapelkin AV, Titirici MM and Sukhorukov GB (2016). In Situ Synthesis of Fluorescent Carbon Dots/Polyelectrolyte Nanocomposite Microcapsules with Reduced Permeability and Ultrasound Sensitivity. Acs Nano  10.1021/acsnano.6b05088

Sun YW, Hernández I, González J, Scott K, Donovan KJ, Sapelkin A, Rodríguez F and Dunstan DJ (2016). Significance of bundling effects on carbon nanotubes' response to hydrostatic compression. Journal of Physical Chemistry C  vol. 120, (3) 1863-1870. 10.1021/acs.jpcc.5b09082

Zhang Y, Ersoy O, Karatutlu A, Little W and Sapelkin A (2016). Local structure of Ge quantum dots determined by combined numerical analysis of EXAFS and XANES data. J Synchrotron Radiat  vol. 23, (1) 253-259. 10.1107/S160057751501913X

2015

Karatutlu A, Little W, Ersoy O, Zhang Y, Seker I and Sapelkin A (2015). Laser-induced particle size tuning and structural transformations in germanium nanoparticles prepared by stain etching and colloidal synthesis route. Journal of Applied Physics  vol. 118, (24) 10.1063/1.4939066

Corsini NRC, Zhang Y, Little WR, Karatutlu A, Ersoy O, Haynes PD, Molteni C, Hine NDM, Hernandez I, Gonzalez J, Rodriguez F, Brazhkin VV and Sapelkin A (2015). Pressure-Induced Amorphization and a New High Density Amorphous Metallic Phase in Matrix-Free Ge Nanoparticles. Nano Lett  vol. 15, (11) 7334-7340. 10.1021/acs.nanolett.5b02627

Chen S, McLachlan M, Sapelkin A and Binions R (2015). Aerosol assisted chemical vapour deposition of transparent conductive ZnO thin films with hexagonal microplate surfaces and ultrahigh haze values. Journal of Materials Chemistry A  vol. 3, (44) 22311-22315. 10.1039/c5ta06029j

Chen S, Carraro G, Barreca D, Sapelkin A, Chen W, Huang X, Cheng Q, Zhang F and Binions R (2015). Aerosol assisted chemical vapour deposition of Ga-doped ZnO films for energy efficient glazing: Effects of doping concentration on the film growth behaviour and opto-electronic properties. Journal of Materials Chemistry A  vol. 3, (24) 13039-13049. 10.1039/c5ta02163d

Karatutlu A, Song M, Wheeler AP, Ersoy O, Little WR, Zhang Y, Puech P, Boi FS, Luklinska Z and Sapelkin AV (2015). Synthesis and structure of free-standing germanium quantum dots and their application in live cell imaging. Royal Society of Chemistry  Rsc Advances  vol. 5, (26) 20566-20573. 10.1039/c5ra01529d

Zhang Y, Karatutlu A, Ersoy O, Little W, Cibin G, Dent A and Sapelkin A (2015). Structure and effects of annealing in colloidal matrix-free Ge quantum dots. J Synchrotron Radiat  vol. 22, (1) 105-112. 10.1107/S1600577514022486

2014

Pavlenko E, Boyer F, Puech P, Olivier P, Sapelkin A, King S, Heenan R, Pons F, Gauthier B, Cadaux P-H and Bacsa W (2014). Origin of mechanical modifications in poly (ether ether ketone)/carbon nanotube composite. Journal of Applied Physics  vol. 115, (23) 10.1063/1.4883299

Ye HQ, Li Z, Peng Y, Wang CC, Li TY, Zheng YX, Sapelkin A, Adamopoulos G, Hernandez I, Wyatt PB and Gillin WP (2014). Organo-erbium systems for optical amplification at telecommunications wavelengths. Nature Publishing Group  Nature Materials  vol. 13, (April 2014) 382-386. 10.1038/NMAT3910

Sun YW, Hernández I, Ghandour AJ, Rice C, Crowe IF, Halsall MP, Sapelkin A, Gonzalez J, Rodriguez F and Dunstan DJ (2014). Resonance Raman spectroscopy of carbon nanotubes: pressure effects on G-mode. High Pressure Research  10.1080/08957959.2013.878714

2013

Pavlov AM, De Geest BG, Louage B, Lybaert L, De Koker S, Koudelka Z, Sapelkin A and Sukhorukov GB (2013). Magnetically engineered microcapsules as intracellular anchors for remote control over cellular mobility. Adv Mater  vol. 25, (48) 6945-6950. 10.1002/adma.201303287

Hatch SM, Sapelkin A, Cibin G, Taylor R, Dent A, Briscoe J and Dunn S (2013). Investigating the source of deep-level photoluminescence in ZnO nanorods using optically detected x-ray absorption spectroscopy. Journal of Applied Physics  vol. 114, (15) 10.1063/1.4824810

SAPELKIN A, Bolmatov D, Karatutlu A, Lyttle W, Trachenko K, Cibin G, Mosselmans F, Dent AJ and Mountjoy G (2013). Structural Origin of Light Emission in Germanium Quantum Dots. Arxiv 

Ghandour AJ, Crowe IF, Proctor JE, Sun YW, Halsall MP, Hernandez I, Sapelkin A and Dunstan DJ (2013). Pressure coefficients of Raman modes of carbon nanotubes resolved by chirality: Environmental effect on graphene sheet. Physical Review B  vol. 87, (8) 10.1103/PhysRevB.87.085416

2012

Granovsky A, Orlov A, Perov N, Gan'shina E, Semisalova A, Balagurov L, Kulemanov I, Sapelkin A, Rogalev A and Smekhova A (2012). Above room temperature ferromagnetism in Si:Mn and TiO(2-delta)Co. J Nanosci Nanotechnol  vol. 12, (9) 7540-7544. 10.1166/jnn.2012.6543

Puech P, Hu T, Sapelkin A, Gerber I, Tishkova V, Pavlenko E, Levine B, Flahaut E and Bacsa W (2012). Charge transfer between carbon nanotubes and sulfuric acid as determined by Raman spectroscopy. Physical Review B  vol. 85, (20) 10.1103/PhysRevB.85.205412

2011

Ghandour AJ, Dunstan DJ, Sapelkin A, Hernandez I, Halsall MP and Crowe IF (2011). Effect of water on resonant Raman spectroscopy of closed single-walled carbon nanotubes. Physica Status Solidi B-Basic Solid State Physics  vol. 248, (11) 2548-2551. 10.1002/pssb.201100074

Ghandour AJ, Dunstan DJ and Sapelkin A (2011). Raman G-mode of single-wall carbon nanotube bundles under pressure. J Raman Spectrosc  vol. 42, (8) 1611-1613. 10.1002/jrs.2905

Pavlov AM, Sapelkin AV, Huang X, P apos ng KMY, Bushby AJ, Sukhorukov GB and Skirtach AG (2011). Neuron Cells Uptake of Polymeric Microcapsules and Subsequent Intracellular Release. Macromolecular Bioscience  vol. 11, (6) 848-854. 10.1002/mabi.201000494

2010

Yashchenok AM, Bratashov DN, Gorin DA, Lomova MV, Pavlov AM, Sapelkin AV, Shim BS, Khomutov GB, Kotov NA, Sukhorukov GB, Möhwald H and Skirtach AG (2010). Carbon nanotubes on polymeric microcapsules: Freestanding structures and point-wise laser openings. Advanced Functional Materials  vol. 20, (18) 3136-3142. 10.1002/adfm.201000846

Chang H, Khan R, Rong Z, Sapelkin A and Vadgama P (2010). Study of albumin and fibrinogen membranes formed by interfacial crosslinking using microfluidic flow. Biofabrication  vol. 2, (3) 10.1088/1758-5082/2/3/035002

2009

Orlov AF, Granovsky AB, Balagurov LA, Kulemanov IV, Parkhomenko YN, Perov NS, Gan'shina EA, Bublik VT, Shcherbachev KD, Kartavykh AV, Vdovin VI, Sapelkin A, Saraikin VV, Agafonov YA, Zinenko VI, Rogalev A and Smekhova A (2009). Structure, electrical and magnetic properties, and the origin of the room temperature ferromagnetism in Mn-implanted Si. J Exp Theor Phys+  vol. 109, (4) 602-608. 10.1134/S1063776109100069

2008

Ghandour AJ, Dunstan DJ, Sapelkin A, Proctor JE and Halsall MP (2008). High-pressure Raman response of single-walled carbon nanotubes: Effect of the excitation laser energy. Phys Rev B  vol. 78, (12) 10.1103/PhysRevB.78.125420

Puech P, Ghandour A, Sapelkin A, Tinguely C, Flahaut E, Dunstan DJ and Bacsa W (2008). Raman G band in double-wall carbon nanotubes combining p doping and high pressure. Phys Rev B  vol. 78, (4) 10.1103/PhysRevB.78.045413

Kartopu G, Sapelkin AV, Karavanskii VA, Serincan U and Turan R (2008). Structural and optical properties of porous nanocrystalline Ge. J Appl Phys  vol. 103, (11) 10.1063/1.2924417

2007

Sapelkin AV, Karavanskii VA, KartopU G, Es-Souni M and Luklinska Z (2007). Raman study of nano-crystalline Ge under high pressure. Phys Status Solidi B  vol. 244, (4) 1376-1380. 10.1002/pssb.200642432

Balagurov LA, Klimonsky SO, Kobeleva SP, Konstantinova AS, Orlov AF, Perov NS, Sapelkin A and Yarkin DG (2007). Ferromagnetism of 3-D transition metals solid solutions in titanium oxides. J Magn Magn Mater  vol. 310, (2) E714-E716. 10.1016/j.jmmm.2006.10.779

2006

Balagurov LA, Klimonsky SO, Kobeleva SP, Konstantinova AS, Orlov AF, Perov NS, Sapelkin A and Yarkin DG (2006). Impact of vacuum thermal treatments on the structure and magnetic properties of titanium oxide films doped with Co. J Phys-Condens Mat  vol. 18, (48) 10999-11005. 10.1088/0953-8984/18/48/027

Kartopu G, Es-Souni M, Sapelkin AV and Dunstan D (2006). A novel SERS-active substrate system: Template-grown nanodot-film structures. Phys Status Solidi A  vol. 203, (10) R82-R84. 10.1002/pssa.200622238

Puech P, Flahaut E, Sapelkin A, Hubel H, Dunstan DJ, Landa G and Bacsa WS (2006). Nanoscale pressure effects in individual double-wall carbon nanotubes. Phys Rev B  vol. 73, (23) 10.1103/PhysRevB.73.233408

Balagurov LA, Loginov BA, Petrova EA, Sapelkin A, Unal B and Yarkin DG (2006). Formation of porous silicon at elevated temperatures. Electrochim Acta  vol. 51, (14) 2938-2941. 10.1016/j.electacta.2005.09.022

Sapelkin AV, Bayliss SC, Unal B and Charalambou A (2006). Interaction of B50 rat hippocampal cells with stain-etched porous silicon. Biomaterials  vol. 27, (6) 842-846. 10.1016/j.biomaterials.2005.06.023

2005

Andrushin SY, Balagurov LA, Liberova GV, Loginov BA, Petrova EA, Sapelkin A, Unal B and Yarkin DG (2005). Formation of porous silicon on a non-conductive substrate and its use as a sacrificial layer. Semicond Sci Tech  vol. 20, (12) 1217-1222. 10.1098/0268-1242/20/12/013

Sapelkin AV (2005). Susan Caroline Bayliss - Obituary. Phys Today  vol. 58, (7) 78-78. 10.1063/1.2012477

2003

Lyapin AG, Mukhamadiarov VV, Brazhkin VV, Popova SV, Kondrin MV, Sadykov RA, Tat'yanin EV, Bayliss SC and Sapelkin AV (2003). Structural and elastic anisotropy of carbon phases prepared from fullerite C-60. Appl Phys Lett  vol. 83, (19) 3903-3905. 10.1063/1.1625432

Greaves GN, Meneau F, Sapelkin A, Colyer LM, Gwynn IA, Wade S and Sankar G (2003). The rheology of collapsing zeolites amorphized by temperature and pressure. Nat Mater  vol. 2, (9) 622-629. 10.1038/nmat963

Brazhkin VV, Lyapin AG, Voloshin RN, Popova SV, Tat'yanin EV, Borovikov NF, Bayliss SC and Sapelkin AV (2003). Pressure-induced crossover between diffusive and displacive mechanisms of phase transitions in single-crystalline alpha-GeO2. Phys Rev Lett  vol. 90, (14) 10.1103/PhysRevLett.90.145503

Kartopu G, Bayliss SC, Karavanskii VA, Curry RJ, Turan R and Sapelkin AV (2003). On the origin of the 2.2-2.3 eV photoluminescence from chemically etched germanium. J Lumin  vol. 101, (4) 275-283. 10.1016/S0022-2313(02)00570-7

2002

SAPELKIN A (2002). Distance dependence of mean-square relative displacements in EXAFS. Physical Review B  vol. 65, (17) 172-184. 10.1103/PhysRevB.65.172104

SAPELKIN A and Bayliss SC (2002). Distance dependence of mean-square relative displacements in EXAFS. Physical Review B  vol. 65, (17) 172104-1-172104-4. 10.1103/PhysRevB.65.172104

Sapelkin AV and Bayliss SC (2002). X-ray absorption spectroscopy under high pressures in diamond anvil cells. High Pressure Res  vol. 21, (6) 315-329. 10.1080/08957950108202590

2001

Vanpeteghem CB, Nelmes RJ, Allan DR, McMahon MI, Sapelkin AV and Bayliss SC (2001). High-pressure high-temperature studies of structural ordering in GaSb. Phys Status Solidi B  vol. 223, (2) 405-409.

1994

BRAZHKIN V, LYAPIN A, POPOVA S and SAPELKIN A (1994). Semiconductor-metal transition in amorphous gallium antimonide at high-pressure. Jetp Letters  vol. 59, 130-134.

TBC

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