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                            Corresponding authors
                                                                                                            
                    
                    
                        
                                a
                        
                        
                            Department of Chemistry, University of Nebraska – Lincoln, Lincoln, NE 68588, USA
                                
                                E-mail:
                                    sinitskii@unl.edu                                                                                        
                                Fax: +1-402-472-9402                                                            
                                Tel: +1-402-617-3543                        
                    
                    
                        
                                b
                        
                        
                            Department of Physics and Nanoscopy Facility, College of Natural Sciences, University of Puerto Rico, PO Box 70377, San Juan, Puerto Rico 00936-8377, USA
                                                                                                            
                    
                    
                        
                                c
                        
                        
                            Department of Chemistry, College of Natural Sciences, University of Puerto Rico, PO Box 70377, San Juan, Puerto Rico 00936-8377, USA
                                                                                                            
                    
                    
                        
                                d
                        
                        
                            Department of Electrical Engineering, University of Nebraska – Lincoln, Lincoln, NE 68588, USA
                                                                                                            
                    
                    
                        
                                e
                        
                        
                            Department of Physics and Astronomy, University of Nebraska – Lincoln, Lincoln, NE 68588, USA
                                                                                                            
                    
                    
                        
                                f
                        
                        
                            National University of Science and Technology “MISIS”, Moscow 119991, Russia
                                                                                                            
                    
                    
                        
                                g
                        
                        
                            Nebraska Center for Materials and Nanoscience, University of Nebraska – Lincoln, Lincoln, NE 68588, USA